Today we've made the WPF sources for the .NET Framework 3.5 SP1 available as download through Visual Studio 2008. The downloadable version of the sources is currently going through its latest tests and I'll make it available as soon as all tests have passed. The sources are available for Windows Vista and all other versions of Windows. The different flavors caused some of the delays but I hope we have overcome all issues and everyone will be able to take advantage of this improved insight in the inner workings of WPF and the .NET Framework.
You can find the instructions on how to configure Visual Studio 2008 and take advantage of the RSCC features on the RSCC web site. We've added some interesting features in Visual Studio 2008 SP1 and I'll make sure to write a blog post about that in the coming days.