Today marks the first day of the BUILD conference.  Recordings of sessions will be available online at http://channel9.msdn.com/events/Build/2012/ within 24-48 hours. 

Here are some keynote highlights that were new or interesting to me. 

Top-line announcements (downloads/releases)

• The Windows Phone 8 SDK is available at http://aka.ms/JenPhoneSDK. The download includes the SDK, free version of VS2012, Blend 5, and emulators.  There are great resources on the Dev Center (http://dev.windowsphone.com) as well.
• Windows Phone 8 developer registration is reduced to $8 for the next 8 days! The process for this is a refund policy. For more information, see http://blogs.windows.com/windows_phone/b/wpdev/archive/2012/10/30/announcing-the-new-windows-phone-8-developer-platform.aspx: “As an added incentive, for the next 8 days individual developers can register for a Dev Center account for just $8 (a 92 percent savings). Please note because this is a very limited time offer. You’ll be charged $99 USD or equivalent in your local currency, and we’ll refund the difference in the next 30 to 45 days.”
• New resources for iOS developers to move to Windows 8: http://www.interop.windows.com.  This covers Installing Windows 8 and the dev tools on your Mac as well as an API Mapping Index that maps common iOS APIs to their equivalent Windows 8 APIs. 

Random points from the BUILD keynote

• 4M upgrades to Windows 8 sold since launch on Friday
• Lots of buzz on Twitter about snapping the Windows 8 Bing app during the keynote. I think a lot of folks haven’t used it this way, and it’s neat functionality: your results list from your Bing query is snapped and then the results open in IE10 in fill mode next to it. So you can look at each result while keeping the result list on the screen and can easily jump between results. 
• A new ESPN app was previewed (not in the Windows Store yet).  Also, Twitter, SAP, and Dropbox announced intention to build Win8 apps for the Windows Store.
• During the keynote, they did a quick review of the Windows Phone 8 feature announcements from its launch event yesterday (like Kids Corner – see below). 
• The story between Windows Phone 8 and Windows 8 is based on how you build it. You can get high code reuse between them, but optimize for the different form factors. They demoed an example of an app that had both a Windows Phone 8 and a Windows 8 frontend. This was not a “code once, run everywhere” scenario but instead a “high code reuse” scenario where the solution has 3 projects: a Windows 8 frontend, a Windows Phone frontend, and a DLL with logic that both of them can use. The two frontends were each optimized for the different form factors.
• Some Windows Phone 8 goodness:
• WP8 delivered on 90% of the top developer requests
• WP8 supports C++
• WP8 Store supports in-app purchases for both consumables and durables
• Gaming middleware support: Unity, SharpDX, etc.
• Test your WP7 apps on WP8, but the backwards compatibility is very high.

Windows Phone 8 launch event highlights (this event was yesterday, but here is a summary of the high points from my Twitter stream)

• 120,000 apps in the Windows Phone Marketplace.  191 countries now have app access.
• There is a new lock screen powered by live apps (and the tiles have more sizes for a customized look just for you). 
• Pandora Radio is coming in early 2013 for Windows Phone 8.  It will be ad-free for 2013, courtesy of Microsoft.
• Data Sense: It compresses data, finds nearby WiFi hotspots, and automatically adjusts behavior as you get near your data limit.  According to testing on the top 100 websites, Data Sense lets you do 45% more web browsing on the same data plan.
• Kids Corner: In Settings, you can customize a different Start Screen of tiles for your kids, and only expose them to certain apps/music/games/pictures of your choosing on your phone. 
• New "room" feature in Windows Phone 8 takes groups to the next level: shared photos, calendar, messages, to-do lists, etc.
• You can easily share documents between Windows Phone 8 and Windows 8 (this uses Skydrive backend).
• 46 of the top 50 apps on competitive platforms are coming for Windows Phone.
• Devices (see here for more details):
• Verizon will carry the Windows Phone 8X by HTC and the Nokia Lumia 822, in stores by Thanksgiving.  Verizon will also have the Samsung Ativ Odyssey by December. 
• T-Mobile will have the Nokia Lumia 820 and Windows Phone 8X by HTC by Nov 14. 
• AT&T will carry the Nokia Lumia 920, Nokia Lumia 820, and Windows Phone 8X by HTC. 
• All devices and colors in the US will be sold at Microsoft Stores.

Windows Phone 8 resources

• Website: http://www.windowsphone.com
• Blog: http://blogs.windows.com/windows_phone/b/windowsphone/
• Videos used at the launch event: http://youtu.be/a4Z1IqQbfxA
• Live blog of launch event: http://live.theverge.com/live-windows-phone-8-event-microsoft/#