The team blog of the Expression Blend and Design
But if you want to continue to use the January CTP of EID then please read this post before rushing off and installing anything.
As you know, the WinFX Runtime Components (RTC) are the redistributables (runtime binaries) needed for executing WinFX applications. You target a particular version of WinFX when you develop your Windows Presentation Foundation (WPF) applications. You'll also be aware that Expression Interactive Designer (EID) is itself a WPF application so it is built to run against a particular version of WinFX, as are the WPF applications you build using EID.So, if you want to continue to use the January CTP of EID then you'll need the WinFX Jan CTP installed on your machine. If you've downloaded and played with the new WinFX Feb CTP then you'll need to revert to the WinFX RTC Jan CTP  in order to continue to use EID.
That is, at least for just a little while longer. We have a March CTP of Expression Interactive Designer under starter's orders as we speak so please be patient just a little longer. And the EID March CTP will work with the WinFX Feb CTP.If you'd like to experiment with the new WinFX RTC Feb CTP  then please do so. If you're a developer-type then you'll also be keen to try out the compatible Visual Studio "Orcas" CTP  which contains a WPF visual designer (code name "Cider"). http://www.microsoft.com/downloads/details.aspx?familyid=61DD9CA7-1668-42E4-BD37-03716DD83E53&displaylang=en http://www.microsoft.com/downloads/details.aspx?FamilyId=F51C4D96-9AEA-474F-86D3-172BFA3B828B&displaylang=en http://www.microsoft.com/downloads/details.aspx?FamilyId=AD0CE56E-D7B6-44BC-910D-E91F3E370477&displaylang=en
In his blog post , Tim Sneath answers the following questions about considering when and where to use the most appropriate presentation layer technology:
In this tutorial, you will process an ADO.NET DataTable into an ObservableCollection ready to be bound to controls within Expression Interactive Designer. The first task requires Visual Studio 2005 and SQL Server 2005 (with the AdventureWorks sample database installed). If you prefer, you can fill an ADO.NET DataTable or DataSet from another source. If you do so then please skip the first task and then adapt the remainder of the tutorial to suit the shape of the data you have. The principles will be exactly the same.
Also remember that there are several tutorials in the Article Categories section over on the lower right of the blog. For other tutorials targeting the Expression Interactive Designer Jan 06 CTP, please see the Samples and Tutorials Gallery  for that product. It's recommended that you begin with the Fabrikam Catalog series of tutorials as these provide the basics on which the other tutorials build.
Because Windows Presentation Foundation (WPF) is based on the .NET Framework, you can customize the functionality of existing control types. You can start with a control defined in a WPF library, derive a new control type from it, and build that into a library of your own. You can draw a control onto the design surface of Expression Interactive Designer just as easily whether it is implemented in your own library or in a WPF library. In this tutorial you will extend the Button control to create an ImageButton control which has a Source property in addition to the standard Content property. You can then specify how the new Source property is to be used by the control by modifying the control's template.
This is to announce that Karsten has a blog post (authored by Andrew Whiddet) on the subject of asynchronous data binding . It's likely to be of interest to you if you're a software developer or you're a designer with a developer sensibility. It's relevant to our previous post about the AdventureWorks Product Photos  sample and tutorial which loads data from a database into a collection ready for data binding inside Expression Interactive Designer. Typically, data access is expensive in time, so a good pattern is to keep the user-interface responsive whilst the data loads in the background as the post discusses.
You'll be interested in this if you (or someone you know) currently attend school/college/university, are 16 years or over, like to imagine, would be keen to earn a few thousand dollars in prize money and a free trip across the world to see the Taj Mahal, want to make friends and contacts in different academic communities globally, and wouldn't mind learning a lot about technology in the process.
Imagine Cup  is an annual Microsoft-sponsored competition that offers contestants the chance to give their ideas exposure, make critical contacts, and experience a true sense of friendship with peers worldwide. The theme of this year’s Imagine Cup is "Imagine a world where technology enables us to live healthier lives".
Also, this year’s competition will have a new track - "Interface Designer". With so many tools and platforms available and emerging that aim to improve users' experiences with hardware and software, the timing couldn't be better!
Here are some links to news and samples from Electric Rain.
Electric Rain RainStorm Newsletter Jan/Feb 2006 
MSN Community Portal 3D UI Concept ApplicationPortal (please visit http://www.erain.com/products/zam3d/examples to see previews of the sample applications) This sample concept portal provides a 3D user interface control that also integrates 2D images that are also databound to provide additional functionality. This sample explores how 3D controls and components may fit into next generation applications.
On the download page above you can also sign up for ZAM 3D new and product updates.
ZAM 3D / Expression Integration White Paper  – Brief overview of how to integrate ZAM 3D XAML in Expression Interactive Designer projects.NEW ZAM 3D to Expression Wokflow Page 
Unni Ravindranathan , Program Manager on Expression Interactive Designer, has an article published on Coding4Fun  called Designing FreeCell using Expression and Visual Studio Toolsets . In the article Unni tells how he re-created the game FreeCell using the January CTP of Expression Interactive Designer and Visual Studio 2005 Express and he describes his experiences on the brief one-day journey and how much fun it turned out to be.
If you're a parent or an educator (or even a kid!) then, while you're looking at the Coding4Fun website, you might be interested in the Kids' Programming Language 
The other way to create a new element is to select the element type in the Library palette and then draw it onto the artboard. When drawing, the parenting rules are different. If a container element is selected and the mouse down gesture of the draw happens inside its bounds, then the selected container becomes the parent. Otherwise the activated element becomes the parent.
That covers how new elements are parented. But what about dragging an existing element to another parent? In Windows Forms, when you drag an element to a new location the design surface re-parents the element inside the front-most container at the mouse pointer. Expression Interactive Designer doesn't assume that you wish to re-parent an element when you drag it to a new position. This is mainly due to (partially) transparent elements. I may want to drag an element from one cell of a Grid to another cell which happens to be behind part of a Canvas with an opacity mask. In this case I don't want to have my element re-parented just because the Canvas is in front of the Grid, and EID leaves the element under its current parent (at the new position) unless I indicate otherwise. Whenever I drag an element into the boundary of a candidate parent container, EID offers the tip: Alt-drag to place into [container_type]. Only if I hold down ALT while completing the drag is the element re-parented.