If you're like me, you're interested in what's new for WPF in the .NET 3.5 Framework after installing VS2008. Luckily there's already many resources available all about. By far the most comprehensive information is on MSDN at the What's New in Windows Presentation Foundation Version 3.5 article.
There's also a great video about it by Kevin Moore on Channel 9 that goes in depth about it.
Other links:
Tim Sneath: What's New in WPF 3.5? Here's Fifteen Cool Features...
SDKTeam: What's New in WPF in the .NET FX 3.5 Beta 2 Release