http://www.microsoft.com/windows/virtualpc/default.mspx
"Highlights
Virtual PC Is Now Free!
Whether Microsoft virtualization technology is an important component of your existing infrastructure or you're just a Virtual PC enthusiast, you can now download Virtual PC 2004 Service Pack 1 absolutely free. Microsoft is also offering the free download of Virtual PC 2007, with support for Windows Vista in 2007."
"Highlights
Virtual PC Is Now Free!
Whether Microsoft virtualization technology is an important component of your existing infrastructure or you're just a Virtual PC enthusiast, you can now download Virtual PC 2004 Service Pack 1 absolutely free. Microsoft is also offering the free download of Virtual PC 2007, with support for Windows Vista in 2007."