I tested the latest rev of the bag-o-tricks on Vista RC1 (which included the .NET Framework 3.0 RC1) with VS 2005 RTM.
All of the samples still build and run fine. "Cider" and the VS beta seem to play along nicely, too.
Hurray for locking down!
(I'm pretty sure anyone can apply to be on the beta of VS 2005 SP1. Go to connect.microsoft.com. Click on Visual Studio and .NET Framework under Available Connections. Fill out the Nomination Survey. At least that's what I did. No promises you'll get in.)