Yep, it's here.
Main page. [0] (Shiny and new).
Download page. [1] (For both x86 and x64 hosts--two seperate downloads)
What's new?
- x64 host support (but only x86 guests)
- Vista host support
- Vista guest support
End of line.
[0] http://www.microsoft.com/windows/products/winfamily/virtualpc/default.mspx
[1] http://www.microsoft.com/downloads/details.aspx?FamilyId=04D26402-3199-48A3-AFA2-2DC0B40A73B6&displaylang=en