Multiple IE Versions on Windows XP
There are a lot of different tips, techniques, and cheats for installing multiple versions of Internet Explorer on a Windows XP machine. Most of them are a huge pain in the butt for the functionality, and even then, when you’re doing it without using a virtual machine, some things still are broken, like cookies and conditional comments.
Well there’s a new program out on the block - Multiple IE by TredoSoft.
The installer allows you to run other versions of IE (versions 3-6) next to your IE 7 installation. The cookies and conditional comments work right, too! There are still a few issues, but it’s clearly better than any other solution out there.
Essentially, you just upgrade your IE6 to IE7 normally so that everything works properly, and then run the Multiple IE installer. 
