Over at the Virtually vista blog there’s a post talking about how to run the RTM of Vista in a virtual machine. Regarding the supported products and additions, the post states:
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.
The only downside we've found with running Vista on a VM is that the precompactor doesn't work - and Vista uses a lot of disk space during the installation, so we haven't been able to compact a dynamic VHD with Vista.You can get both VPC 2007 and Virtual Server 2005 R2 SP1 Beta form http://connect.microsoft.com.