WPF DataGrid CTP
Visual Studio 2008 SP1 and .net framework 3.5 SP1 released versions are now available. See here the summary of fixes in this service pack. What is also now available is the WPF DataGrid CTP Release. See here for details on its features. It is available on WPF Codeplex site for download along with some information on WPF Futures.
A sample that Vincent has put together for DataGrid can be seen here. I am going ahead and downloading the DataGrid control. If you are also working with this version, do share your feedback on this control.