The Windows Vista Developer Center on MSDN has been scrubbed, polished, reorganized, blown dry, and is now free to peruse. The developer center now includes easier navigation, links to over fifty "How Do I" videos, RSS feeds for the Windows Shell team's blog, Shell:revealed, and a ton of content about why you should develop applications directly for Windows Vista. Just take a look at the What's New in Windows Vista page, and use that as your springboard to identify useful new technologies and to find relavent materials throughout MSDN and TechNet.
Seriously, the reorganization is a ton of help in getting into where you need to be.