Virtual PC 2007 Beta is available for download from http://connect.microsoft.com.
Ever since I switched to Windows Vista I had issues with running Virtual PC 2004. Biggest problem was that the screen would no longer repaint itself upon actions done inside the VPC image. Blind typing extreme... but it wasn't that funny. Also, desktop composition was out of the question, but with showstopper nr. 1, I couldn't be bothered with this one. Maybe a graphics card driver issue (different Vista builds, same results).
First mission after installing Virtual PC 2007 Beta is running an old image that never worked properly. And the result is excellent! That old image worked without a hitch. Desktop composition, ehr.. Aero Glass, is still working and the screen refreshes nicely.
Yes, it's a beta, and this is by no means a thorough test that I'm doing, but my first impression says victory.
Now, on to downloading and trying out that other image. Ouch.. four hours remaining.