Microsoft has updated their Internet Explorer Application Compatibility VPC Images

VPC Hard Disk Image for testing websites with different IE versions on Windows XP SP2, Windows XP SP3 and Windows Vista

This download page contains four separate VPC images, depending on what you want to test.

IE6-XPSP3.exe contains a Windows XP SP3 with IE6 VHD file
IE7-XPSP2.exe contains a Windows XP SP2 with IE7 VHD file
IE8RC1-XPSP3.exe contains a Windows XP SP3 with IE8 RC1 VHD file
IE7-VIS1.exe+IE7-VIS2.rar+IE7-VIS3.rar contain a Vista Image with IE7 VHD file.

Note: For The Vista image, you will need all three files, downloaded and in the same directory, then simply run IE7-VIS1.exe.

This VPC image will expire in April 2009.

IE App Compat VHD (updated)