Since 2007, Microsoft has been offering free copies of Windows XP and Windows Vista for download, in order to make up for a handicap specific to the Windows client, namely the fact that two different versions of Internet Explorer cannot be installed and run simultaneously on the same operating system. While it is cooking the first Release Candidate build for Internet Explorer 8, the Redmond company is also supporting Internet Explorer 7 and Internet Explorer 6, a context in which it is a pain for developers to test their content on all versions of IE.

The situation has caused Microsoft to come up with the Internet Explorer Application Compatibility VPC images, a solution designed to circumvent the limitations of IE running on Windows via virtualization.

With the Internet Explorer Application Compatibility VPC images, Microsoft is offering developers no less than four free copies of Windows packaged as Virtual Hard Disk Images and designed to integrate with the company's free virtualization offerings. The four VHD downloads feature a new release date, just ahead of the end of 2008, although the launched products are similar to those made available in August 2008, following the availability of Internet Explorer 8 Beta 2.

“VPC Hard Disk Image for testing websites with different IE versions on Windows XP SP2, Windows XP SP3 and Windows Vista,” Microsoft revealed. “This download page contains four separate VPC images, depending on what you want to test: IE6-XPSP3_VPC.exe contains a Windows XP SP3 with IE6 VHD file; IE7-XPSP2_VPC.exe contains a Windows XP SP2 with IE7 VHD file; IE8B2-XPSP3_VPC.exe contains a Windows XP SP3 with IE8 Beta 2 VHD file; and 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.”

According to Microsoft, all the VPC images are time bombed and set to expire in January, 2009. In early 2009 the company plans to deliver Internet Explorer 8 Release Candidate 1, having already made available the pre-RC Partner Build. After the availability of IE8 RC, the Redmond giant is expected to deliver a fresh set of VPC images with a new expiration date.

Internet Explorer Application Compatibility VPC Images are available for download here.