Well, at last we've come to this. It's been almost a year since my first post to this blog, and look how far we've come! Windows Vista has RTM'd and is now available to Volume Licensing customers and to MSDN and Technet subscribers. Looks like I'm going to have to change my blog's tagline!
So, how do you get Vista running in a Virtual Machine?
If you're using Virtual PC, you should be using the VPC 2007 Beta - the additions that ship with that product work just fine in Vista.
If you're using Virtual Server, you should use the VS 2005 R2 SP1 Beta - those additions work with Vista as well.
If you're not into using a beta product right now, it's still possible to run Vista in a VM, but I would definitely recommend using the additions from the products above - you'll get a significant performance increase.