Tim Sneath

Congratulations to Martin Grayson and team for building one of the smartest Silverlight 2 demonstrations I've seen to date. I saw parts of this demo a month ago when I was in the UK, and I'm delighted it's now released.

Whether or not you're involved in the healthcare sector, this demo does a great job of showing how Silverlight 2 can transform web-based application development. We're already starting to see many real-world applications using Silverlight 2, even in its beta 1 stage; I'll post a list of the best ones I've collected before the end of the week. With a beta 2 release not far away, momentum is continuing to grow. And keep an eye on this blog first thing Friday morning for a separate exciting announcement (he said elusively)...

I've posted a few times about issues relating to enterprise distribution of Silverlight, and I thought I'd mention one additional topic that came up during a customer tour that I've been on for the last ten days.

If you're a systems administrator, one of the aspects of Silverlight that concerns you is probably controlling the distribution of updates. In general, enterprises like to control their desktop and laptop environments to ensure no sudden surprises are caused (for example, by a runtime update that breaks a commonly used application). So some people may wish to dial down the update settings that are optimized for end-users when Silverlight is running in a corporate environment.

Silverlight supports enterprise rollout via WSUS and we provide guidance on how to roll it out across an enterprise via other means such as Group Policy (using the EXE-based installer). Silverlight is installed via a normal MSI plus an MSP-based patch which can be chained through a variety of means. Updating Silverlight to the latest revision can be done automatically or manually (by pushing out the latest MSP).

There are two different knobs an enterprise administrator can turn to control how updates are applied to the runtime:

• Firstly, if the enterprise sets the UpdateMode DWORD registry value under the HKLM\Software\Microsoft\Silverlight key to 2 then the Silverlight auto-updater will be disabled (i.e. it won't automatically check for updates or try to install them). This is the equivalent to an end-user choosing the Silverlight Configuration dialog and manually disabling auto-updates from the Updates tab.
• Second, the feature that allows a non-admin to patch Silverlight on Windows Vista without requiring admin elevation is not a Silverlight feature: it's a feature of Windows Installer which can be disabled if the admin wants to do so (and is indeed off-by-default in Windows Server 2008). You can switch this off using Group Policy by setting the DisableLUAPatching property. More information on UAC Patching can be found on MSDN.

If an enterprise disables the LUA patching feature in MSI and does not give their users administrative access to machines then users will not be able to install, remove or patch Silverlight. Only the enterprise administrator could touch the files. Obviously, it's important that someone is actively monitoring and distributing patches; as with any runtime for any operating system, without any means to fix potential security vulnerabilities, users' machines are at risk.

Many thanks to Bob Pomeroy for providing the technical detail behind this post. Hopefully this is helpful to those of you who need to persuade your IT department that Silverlight is "safe" for corporate adoption.

We released a minor maintenance update to Silverlight 1.0 over the weekend (internally known as GDR3, where GDR stands for "General Distribution Release"). I'm sure most readers of this blog already have Silverlight 2 Beta 1 installed on their own machines, but if you're building a site for the tens of millions of users that already have Silverlight installed on their machine, you'll be pleased to know that we're continuing to service the 1.0 release to take account of customer-reported issues.

The latest release is live now on the web for both Mac and PC; it reports itself as 1.0.30401.0 (where the build number indicates that it was compiled on April 1st). The changes are minor in nature and shouldn't affect existing applications; they include an audio bug fix for nForce 4 motherboards, an update to support custom parameters in ASX playlists, fixes to font support on Mac OS X Leopard and improved multi-language support during installation and update.

As ever, the way to check which version you're running is to right-click on some Silverlight content and choose the Silverlight Configuration context menu option; on a Macintosh, it's visible by browsing to the Silverlight run-time in its installation location in the browser Plug-Ins folder. Incidentally, it seems that most people don't realize that we publish release notes that highlight the deltas from one release to another (admittedly, the link is pretty buried, so it's worth adding to your favorites).

The jolly chaps at Conchango are setting up a user group in London to focus on Silverlight, and the first meeting is tomorrow! By chance I'm actually in the UK right now on something of a customer tour, so I plan to be there myself and give a bit of a status update on Silverlight 2 and WPF. Should be a fun evening - pizza and beer is provided, and the event kicks off at 6:30pm.

Full details and registration information are on the Facebook event site or on one of the Conchango blogs. If you're working in London, why not head over to London Bridge and come and say hi?

Just loved the team's latest Silverlight video. Props to Adam, Laura, Nic, Monica, Dan, Scott and Tina.

As many people will have noticed, we released Windows Vista Service Pack 1 this week (read about the notable changes here). Aside from the inevitable bug fixes and enhancements to support new hardware types, one of the underlying changes is that SP1 brings the Windows Vista and Windows Server 2008 codebases together.

This is a big deal, but it's surprising how few people have noted it: this is the first time we've ever had a common codebase for Windows that goes all the way from a budget consumer PC right up to a mainframe-class datacenter server. Internally to Microsoft, this makes it easier for us to provide sustained engineering on the product: if we want or need to update a system component, we only have to produce two binaries (x86 and x64) for all languages and product editions. Compare that to the days of Windows XP/2003, when we had maybe 25 different language editions and x86 and x64 variants for both client and server OS releases, and you can see how the testing matrix has become a lot simpler! Externally, the benefit is of course that simply by updating to SP1, you get the benefit of a kernel that has been through an extensive server-hardening process. (Check out this Channel 9 video I recorded last year with Eric Hanson to get just a small flavor of the stress testing work that we do with every build.)

Beyond the kernel and subsystem improvements, Windows Vista SP1 brings major improvements to IIS 7. Comparing the original Windows Vista "RTM" version against that shipped with SP1 is like comparing the basic and premium models of a car - the SP1 version of IIS contains all the features added to create the server-strength edition (with the caveat that Windows Vista SP1 is obviously not licensed for use as a commercial-scale production Internet web server). As a crude measure, compare the two screenshots of the administration console below - the left image is of Windows Vista RTM, the right is of SP1:

You'll see other changes to Windows Vista that affect certain relatively niche groups of developers. Direct3D receives a minor update to 10.1; there are new APIs to control the Data Execution Protection and Kernel Patch Protection features; and there are new cryptographic and random number generation algorithms available for developer use. As ever, more information about these features can be found in the Windows SDK.

As a .NET developer, you'll notice that Vista SP1 updates the installed .NET components to .NET Framework 3.0 Service Pack 1. The good news is that many of the enhancements from .NET Framework 3.5 are included in 3.0 SP1 - for example, of the list of fifteen enhancements to WPF described in this blog post, everything apart from System.AddIn and the Firefox XBAP support is included in Windows Vista SP1. This is a little bit confusing, but it probably helps to know that each of the last .NET Framework releases have built on top of each other, rather than existing side-by-side. The diagram to the right demonstrates this.

As a result, all the CLR and class library enhancements that were made to existing assemblies in 3.5 are incorporated in 3.0 SP1 (mscorlib.dll is updated from 2.0.50727.312 to 2.0.50727.1434); the binaries are identical to those shipped with .NET Framework 3.5. The only difference between 3.0 SP1 and 3.5 is that 3.0 SP1 doesn't have any of the new assemblies ("green bits") added in 3.5 for new capabilities like LINQ. Of course, if you've already installed .NET Framework 3.5 on your Windows Vista machine prior to installing SP1, you'll still have the full 3.5 release on your machine afterwards.

The many other nice features in SP1 for end-users and IT Professionals are outside of the scope of this entry, but suffice it to say that some of the major peeves have been addressed: UAC is less aggressive, file copy performance has been greatly improved (and it takes less time to "estimate"!), application compatibility is better, resuming from standby is faster, and over a thousand bugs have been fixed. For more detail on all these items, check out the main Windows Vista Service Pack 1 site.

It's worth noting in closing that many of the above fixes at least have been delivered via Windows Update over the last twelve months. We're moving away from the old-school approach where service packs were the main way that fixes were delivered to a more agile model where patches are available via Windows Update (or its enterprise equivalent, WSUS) and then rolled into a service update at a later stage. The goal is to reduce the gap between us fixing something and you seeing the results of that fix.

Well, what are you waiting for? Go install Windows Vista Service Pack 1!

Following on very nicely from my last post on deploying Silverlight content to your own production server, I'm pleased to announce that Silverlight Streaming has added full support for Silverlight 2 applications. As well as adding the basic support, the team have put a lot of work into simplifying the process of uploading and validating your application. Here's a basic walkthrough:

1. Create your Silverlight 2 application using Visual Studio or Expression Blend, do all the usual test / debug steps, etc.
2. Create a manifest file named manifest.xml, that describes how you want the control to be hosted. Here's a simple sample you can use as a template:

   <SilverlightApp>
     <version>2.0</version>
     <source>PopTheBubble.xap</source>
     <width>400</width>
     <height>300</height>
     <background>white</background>
     <isWindowless>false</isWindowless>
   </SilverlightApp>

3. Zip your application .xap and manifest.xml files together into one file.
4. Go to silverlight.live.com and upload the application.
5. You're done! Now you can embed the resulting content in any web page with an iframe or the sample code provided.

As a small example, here's a mini-game called PopTheBubble that you can learn to build by following the Silverlight 2 fundamentals hands-on lab. Click on as many bubbles as you can before the timer runs out - have fun!

Deploying Silverlight content to a production web server is a pretty easy process. Despite occasional misconception, Silverlight doesn't require a Microsoft-based web server: Apache can host up Silverlight content just as happily as IIS.

But there's one little gotcha: web servers are typically configured to only serve up a limited set of known file extensions as static content. That's all well and good, but Silverlight introduces two new file extensions (.xaml for loose XAML files and .xap for the zip-based binary packaging format). As a result, you need to add the MIME types for those file extensions to your web server so that it recognizes Silverlight content appropriately. Here are the MIME types you need to add to the server configuration:

That's all you have to do. Unfortunately, it's not possible to provide generic instructions for how to add MIME types, as it varies from server to server, but here are some links for various common web servers:

• Apache (2.0, 1.3)
• IIS (7 / 6.0 / 5.0 / 4.0)
• lighttpd
• Sun Java System Web Server

While you're updating the list of MIME types served, you might want to also add the relevant types to your web server to support WPF and ClickOnce applications. Here are the additional items you'll need:

But what if you're hosting your Silverlight application on a shared hosting service and your hoster doesn't give you access to change these settings? The good news is that there are two options available to you. Obviously, you could take advantage of Silverlight Streaming, our free hosting service for up to 10GB of Silverlight content.

Alternatively, you can "cheat" the web server by renaming the XAP file extension to a compatible MIME type. The XAP container is ZIP-based, so you can simply rename the output file from .xap to .zip and change the source param within the object tag contained in the HTML file to point to the new file location. Click on this hyperlink to see the technique in action - it's a plain HTML file that points to a ZIP file (containing the Silverlight content).

One last piece of good news: IIS 7, included in Windows Server 2008, already includes all the relevant MIME types for both WPF and Silverlight, including both .xap and .xaml extensions, so if you're using Windows Server 2008, you're all set. (The same applies to a clean install of Windows Vista SP1, although if you upgrade from the RTM to the SP1 release, your settings will remain unchanged until you uninstall and reinstall the IIS feature).

It can be pretty hard to keep everything up-to-date on a developer workstation these days. With so many CTP releases, betas, and service packs, I know I often realize that my own machine is behind in one area or another.

One particularly worthwhile update that might have missed your attention over the last couple of weeks is a new release of the Windows SDK, focused on enhancements in the .NET Framework 3.5, Windows Vista SP1 and  Windows Server 2008. Amongst other changes, this updated SDK has new documentation that covers all the new classes in WPF 3.5 (e.g. UIElement3D, System.AddIn, LINQ-based data binding), a variety of new samples for common Windows services such as User Account Control, Windows Search, Windows Error Reporting, Speech, and a range of shell APIs. If you've not installed the Windows SDK before, another incentive is a ZIP file containing over 100MB of sample WPF code (check out %ProgramFiles%\Microsoft SDKs\Windows\v6.1\Samples\WPFSamples.zip).

After installing the Windows SDK, you'll want to do two things:

• Run the new Windows SDK Configuration Tool (Start / Programs / Windows SDK v6.1 / Visual Studio Registration) to ensure that this is set as the default help collection in Visual Studio
• Follow this workaround to fix a XAML Intellisense bug that will be very irritating if you're a WPF developer.

For more information on the Windows SDK, check out the team's blog or visit the recently overhauled Windows Vista development center on MSDN.

A confession: I'm really bad at tipping.

It's not that I'm deliberately ungenerous, but simply that I never know how much to give. The UK isn't really a nation for tips: outside of restaurants, it's not something that's particularly expected, which means that here in the US I'm a complete novice at the art. The result is that sometimes I lavish cash like Sinatra on surly and unhelpful staff, while at other times I completely blow an opportunity to recognize excellent service.

To my embarrassment, I've only lately realized that it's polite to tip housekeeping staff at hotels. I determined to rectify my error this week while staying at the Venetian hotel in Las Vegas for an event, and so I dutifully left a small amount on my bed when I left for the day. To my surprise, when I returned to my serviced room, I noticed that my toiletries had been "upgraded" from the uninspiring generic items that first adorned my room to some rather impressive high-end replacements.

Next morning, I determined to show my gratitude for such thoughtfulness, and left a slightly larger amount on my bed. On returning later, I discovered that not only had the toiletries I'd stashed in my suitcase been replenished, but that I'd acquired still additional items, including a "gentleman's kit" of useful travel accessories. This turned into something of a game: the third morning, I excitedly tipped a little yet more out of fascination to see what would happen (a small vase of flowers and a Loofah sponge). For once, I was rather disappointed that I had to check out; it would have been very tempting to have upped the ante dramatically further to see what the ultimate reward would have been!

As well as discovering a new aspect of the service culture in the US, I also discovered that there are a lot more fun ways to "gamble" your money in Las Vegas than putting it into a slot machine. And just so I don't come across as bragging about my largesse, I should note that the very same evening I horrified a colleague of mine for innocently tipping just 5% on a bar bill (I figured this was a pretty good wage given the size of the bill, but I was apparently so far out that I could have had the dregs of my drink poured over me!). I've still got plenty to learn, it seems.

I'm going to be "live blogging" the Steve Ballmer keynote this afternoon at this URL. Keep this blog post bookmarked and start hitting "refresh" shortly after the keynote starts at 1pm Pacific / 9pm GMT. Or simply tune in to the webcast (750kbps, 300kbps, 100kbps) and watch it live yourself!

1:04pm - Ray Winninger (my boss!) is on stage to announce MIX09, taking place here at the Venetian Hotel in Las Vegas between March 18th-20th, 2009. No - registration hasn't opened yet!

1:07pm - Guy Kawasaki and Steve Ballmer are now sitting in comfy chairs, ready for Q&A.

1:08pm - Guy: why do you want to buy Yahoo? Steve: we've shown tenacity around advertising. Search is the killer feature for online advertising. You could say that we're not where we'd like to be, but we're very committed. Yahoo seems to be a way to accelerate that because of the required critical mass. "What's the current state of the offer?" Steve: We've made an offer - that's all I can say!

1:13pm - Guy: so you're telling me you're an underdog? Steve: Yes, you could say that, for this space.

1:14pm - Guy: I know this won't leave the room, but I use a Motorola Q phone running Windows Mobile, not an iPhone, because I need Exchange.

1:16pm - Guy: tell us about the deal with Facebook. Steve: again, it's about advertising.

1:17pm - Guy: what drives you? Steve: Three things: firstly, I love what I do - bringing out great products like Silverlight 2 and IE 8. Secondly, I get to work with some of the smartest people in the world. Lastly, I enjoy a challenge.

1:19pm - Guy: can you describe a typical day in the life of SteveB? Steve: there are three kinds of days. Sometimes I'm outside of Redmond meeting with customers, flying around the world. Sometimes I'm in the office with back-to-back strategy meetings. Sometimes I have a day where I can think, write and research where there's only perhaps one meeting and I can really focus on strategy. Guy: how much email do you have? Steve: I get perhaps sixty emails a day. Guy: really? I don't believe it. Steve: why do people get a lot of mail? Human beings aren't abusive in general, they send thoughtful, constructive mails. I might get more than sixty tomorrow, of course!

1:23pm - Guy: can you talk about Bill's departure? Steve: he's very fortunate. He's had something to build professionally in Microsoft, and now he's got a second opportunity with the foundation. You know, the company isn't reliant on Bill for new ideas - we've got so many amazing people.

1:25pm - Guy: what's the marketing pitch to recruit young people, particularly now "the stock profit has been made"? Steve: surprisingly, it's almost identical to what it used to be. Even in the early days, people didn't expect to get rich on stock at Microsoft. In the early 90s, we thought it had gone as high as it could go. There aren't many companies where you can get a 10x stock appreciation: it's usually a startup, and most startups fail.

1:28pm - Guy: my kids have no history of the OS and desktop wars - they think of Microsoft just as the Zune and Xbox company. Steve: the opportunity is for us to make great products. For the 17m people who own Xbox 360, or the 10-11m people who are Xbox Live subscribers, but even kids find themselves using office productivity applications for homework.

1:31pm - Guy: tell the audience about your strategy for Silverlight. Steve: there's been a big fork in the road historically - either I build something that's easy to deploy through the browser, or I build a powerful, rich desktop application. Over time, we're trying to bring those two worlds together, so you truly get the best of the Internet and the best of the PC all in one place. We announced Silverlight at MIX07, and we're already seeing 1.5m downloads a day. Windows Presentation Foundation is also seeing lots of momentum.

1:34pm - Guy: don't Apple do a great job with design? Isn't my MacBook Air wonderful?! Steve: it weighs more than my machine and it doesn't even have a DVD drive. Guy: who needs a DVD drive? Steve: you tell that to your kids on a long flight! Let's take that machine away and give you something that's got a full set of features, and then we can talk.

1:35pm - Guy: do you think there's a risk that Microsoft is losing its focus? Steve: you move forward or backward.

1:39pm - Guy: let's talk about Firefox and IE. We're investing heavily in Internet Explorer - lots of browser innovation. Guy: what about IE on the Mac? Steve: how do I say this sensitively? Of all the places we could put our energy for innovation, porting our browser to the Mac is fairly low down the list.

1:42pm - Guy: I've got to be honest, and admit that I've been doing an increasing amount of work with Microsoft over the last few years, and I have to admit that I've seen a change in Microsoft. The "new" Microsoft employee is different - not arrogant, better at responding than other companies. Dan'l Lewin and the guys down in Silicon Valley are doing a great job of bringing Microsoft to people who might not otherwise experience the company.

1:44pm - Attendee: what about Adobe? Steve: Adobe are a competitor, of course; but we also appreciate the innovation they've done with technologies like PDF.

1:46pm - Attendee: .NET is great and there's been lots of innovation on this side of the developer platform; why did IE get left out for so long? Steve: partly because Internet Explorer was shipped as part of the operating system and there was a long gap between Windows XP and Windows Vista. You won't see that kind of gap again - we now understand how to get things decoupled sufficiently to develop innovations separately from the OS and then bring them back later.

1:48pm - Attendee: if Microsoft take over Yahoo, what will you do with all those PHP applications? Steve: obviously we shouldn't have two of everything - two search services, advertising services, mail services etc. Some of the technology would come from the Microsoft side, some from the Yahoo side. I'm sure that when all is said and done, some of them would still be running. There will be lots of innovation in the core infrastructure, and over time, probably most of the big applications on the Internet will wind up being redone, but for the forseeable future, we would be a PHP "shop" if we own Yahoo as well as an ASP.NET shop. One of the key things we've done in Windows Server is to ensure that it's the best place for PHP applications.

1:50pm - Attendee: what synergies do you see with Yahoo? Steve: scale is a form of synergy. The more search share, the more advertisers you have, the more bidding you get in keywords, the more revenue you get. Google has a bigger body of ad inventory than either Microsoft or Yahoo do individually and bringing the companies together can result in benefits.

1:52pm - Attendee: you did a great job by acquiring FAST Search - it's amazing technology. Steve: we're in the regulatory phase here; we love the company and we'll have more to say when we're through the approval process.

1:54pm - Attendee: what is Microsoft going to offer in terms of cloud computing? Steve: with the launch of Hyper-V, it makes it easy for anyone to set up a datacenter for cloud services. Ray Ozzie hinted at some plans we're going to announce later in the year.

1:55pm - Attendee: any news about Silverlight for the iPhone? Steve: this is of course interesting; we'd love to see Silverlight in as many places as possible. Apple today announced an SDK and runtime, but they want 30% of all revenue that you make on it. This is a great model if you can make it stick, I'm not sure that many developers will be interested in that arrangement.

1:57pm - Guy: what kind of mobile phone do you have? Steve: I'm always rotating around from one phone to another.

1:58pm - Attendee: when are we going to see Silverlight as the default for Microsoft properties, e.g. Hotmail? Steve: you'll see it in a lot of places over the coming months and years. Of course, we have the same codebase issues as everyone else- it's only when we update a product that it makes sense to consider changing the delivery mechanism.

1:59pm - Attendee: can you tell us about your plans for the health sector? Steve: health is the only vertical we've really invested in, both because it's the largest sector and because there's a lot of potential there. We have technologies like HealthVault that are trying to bootstrap the idea of a portable medical record.

2:01pm - Attendee: what are your plans for Blu-Ray now that it's won the format war? Steve: we liked HD DVD because it was there early, but we're not a player manufacturer. We'll add support for Blu-Ray, of course, and we already have support in Windows Vista, for example. It's interesting to note though that there is a move towards digital downloads: maybe not in the next year or two, but certainly in the medium-term.

2:05pm - Attendee: thank you for DreamSpark and Channel 8: this really helps us out as students. We've got the tools - how can you help us out with servers / services? Steve: plenty of hosting companies out there. (Tim: don't forget the MIX Sandbox either!) Students can also check out these sessions at http://sessions.visitmix.com.

2:12pm - And we're done!

I mentioned yesterday that the Hard Rock memorabilia application was live already at http://memorabilia.hardrock.com. The AOL Silverlight-based mail client is not live yet, but they've just opened up their pre-registration site for testers who want to be the first to try out the new application, in just a few weeks' time. You can sign up here: http://ria.mail.aol.com/.

In case you didn't see the demo of this application either at the keynote or online, it's cool because it shows how Silverlight isn't just about flashy gradients or animations, but it's emerging as a solid RIA framework for building web-based applications that have the performance of a desktop application. It's not that you can't build a mail client in AJAX, obviously, but having client-side compiled .NET code, isolated storage for caching and a powerful rendering engine that supports control templates means that you're not relying on a chatty back-and-forth with a high latency remote web server. I've been using the application first-hand for demos over the last week, and there's nothing like it for performance - being able to flip back and forward in milliseconds from folder to folder takes all the pain out of web-based mail. This application makes AOL a real contender in the free webmail space, and it really raises the bar for the experience that users will expect from a web-based mail interface.

Make sure you sign up!

We're already starting to see some cool samples that use Silverlight 2 really effectively. Prior to MIX, we had a small private beta running to get some early feedback on the builds that we were producing, and a few folk made really good use of this time to build some interesting ideas out.

This one is one of my favorites: TextGlow is a Silverlight 2 application that reads Word .docx files. The Open XML format is an ECMA-ratified standard, and having a web-based runtime with the power Silverlight makes it possible to accomplish something that I don't think you could do easily with any other technology. TextGlow downloads Word documents asynchronously, opens them as ZIP files, parses them with LINQ-to-XML and then renders them using the WPF-based text and graphics APIs.

This is a big deal, and not just because it's a cool Silverlight sample. In years gone by, if you wanted to share a document on the web, you'd typically have converted it to PDF format (assuming you had the full version of Adobe Acrobat on your system). Having two versions of the document meant changes were hard: you had to reconvert the document every time you made a change or the PDF file wouldn't match the current version. TextGlow solves that problem by providing cross-platform access to the source Word document, regardless of whether you have Office installed on your machine or not. The version of TextGlow above is a demonstrator, but there's endless potential for this. I hope the SharePoint team is watching, in particular.

TextGlow was written by Intergen, a New Zealand-based partner. You can read more about the way the application was built from one of the developers, James Newton-King.

OK, so you've got all the bits downloaded and installed on your machine. What's the best way to start to get familiar with everything we've added to Silverlight 2?

Well, you could do worse than start with the thirty page hands-on lab that I spent part of last week frantically working on! This lab takes you through the various steps of creating and packaging an application, figuring out layout and controls, all the way through to creating a mini-game using Silverlight 2. It's a good lab to get familiar with XAML, Expression and the new Visual Studio tools.

Once you're done with that lab, there are a number of others that you can go through to add depth to your knowledge, written by Adam and Laurence. Download them here. And if even that isn't enough for you, there are some tutorials here that Jesse Liberty has been working on. Hopefully that's plenty to get you up and running for now!

Here's a consolidated list of all the key downloads you'll need to update your developer workstation to the latest and greatest technologies announced this morning:

• Internet Explorer 8 Beta 1
  • Windows Vista / Windows Server 2008 (x86)
  • Windows Vista / Windows Server 2008 (x64)
  • Windows XP (x86)
  • Windows Server 2003 SP2 (x86)
  • Windows Server 2003 SP2 / Windows XP (x64)
• Silverlight 2 Beta 1 Runtime
• Silverlight 2 Tools for Visual Studio 2008 and SDK
• Updated: Source Code / Unit Tests for Silverlight 2 Controls
• Expression Studio 2 Beta (contains Blend, Design, Encoder, Media and Web)
• Expression Blend 2.5 March 2008 Preview
• Updated: Expression DeepZoom Composer
• ASP.NET MVC Preview 2

A couple of tips:

• The Silverlight 2 Tools release (third item above) includes the Silverlight 2 runtime and the SDK. You don't need to install the runtime separately first: just run the tools installer and you'll have everything you need.
• The Visual Studio extensions don't work with the Express editions - make sure you've got the full Visual Studio 2008 installed before attempting to install them.
• If you installed Silverlight 1.1 Alpha, uninstall it first, along with any related tools or SDKs before installing Silverlight 2 Beta 1. I watched someone get into a bit of a mess this morning by trying to update Silverlight 1.1 Alpha in-place. Fortunately, they were still able to uninstall and reinstall, but you're definitely best to start with a clean machine.

Have fun!