Al ot of people have been asking me about this and I'm happy to inform you that you can now download Virtual PC 2007 Beta from the Connect website.
I've been using this for a couple of weeks now and the changes are really cool. There are a lot of new changes with the major one being you can use Windows Vista as a host and as a Guest. Also running is close second is hardware virtualization for both AMD and Intel chipsets if your hardware supports it.
Check out the download at the Connect Website and the Virtual PC Guy's website for more details on Virtual PC 2007.