Microsoft has released Windows XP Mode Beta and Windows Virtual PC Beta for the Windows 7 RC. Windows XP Mode is a free Windows XP virtual machine for Windows 7. Windows XP Mode requires Virtualize Technology on AMD and Intel processors. On AMD processors the technology is called, AMD-V (virtualize) and on Intel is called AMD-VTx (virualize technology). Virtualize Technology has been around for three years now and is on most AMD processors but not all Intel processors. Virtualize Technology has to be enabled in the PC BIOs.
Pentium Extreme Edition 955 and 965 (not Pentium 4 Extreme Edition with HT)
Pentium D 920-960 except 945, 935, 925, 915
some models of the Core processors family
some models of the Core 2 processors family
Xeon 3000, 5000, 7000 series
some Atom chips
all Intel Core i7 processors