Visual Studio 2008 Beta 2 and the .NET Framework 3.5 Beta 2 are now available! You can download them here. Read more about this release on Somasegar's annoucement post.
What's new in WPF? Here's a non-comprehensive list:
o WPF builds on the new add-in model in .NET Framework 3.5 Beta 2 to allow developers to create visual add-ins, where add-ins provide UIs that are displayed by the host application. You’ll find the add-in types in the System.AddIn namespace in System.AddIn.dll, System.AddIn.Contract.dll, and System.Windows.Presentation.dll.
o XBAPs can now run in FireFox.
o Cookies can be shared between XBAPs and Web applications from the same site of origin.
o Improved XAML intellisense experience for higher productivity.
o Data binding and journaling by URI work together.
o The data validation model now supports the IDataErrorInfo interface. (new class: System.Windows.Controls.DataErrorValidationRule)
o Improvements have been made to BindingListCollectionView to provide better support for binding to a collection that is of type BindingList and for LINQ.
o The behavior of data bindings with a CollectionView over an IEnumerable has been improved to provide better performance and better support for binding to results that are produced by LINQ.
We'll be sharing samples here for you to play with - stay tuned!