Recently I had a requirment to run multiple versions of IE for testing , after investigating I came accross this link and found it very helpful.

http://www.skyzyx.com/archives/000094.php

Zipped versions of IE are available from this site and they run parallel to IE original install, the only issue is that cookies are not set by these versions, so you need to access a site first in regular main IE and then copy over the URL to previous version of IE like 5.5 and 5.01.

Microsoft Class Server makes it easy for school districts to create, deliver, and grade standards-aligned tests and lessons over the Web—helping teachers track and improve student achievement against local curriculum standards, and meet the challenges of No Child Left Behind.

Class Server Homepage

Nice website with movable type styles

http://www.movablestyle.com/