For web development testing purposes it would be very handy to have multiple verisions of Internet Explorer (IE) on Windows. Luckily it is possible.
It is possible to run multible versions of Internet Explorer in standalone mode. First Joe Maddalone introduced this in Multiple Version of IE in Windows XP Pro. Manfred Staudinger perfected the standalone versions in Taming Your Multiple IE Standalones by adding IE version numbers to the title bar of the standalone browser window.
Now there are two options to install different versions. You can download readily packaged versions separately from Evolt's archive. You just have to unzip the packages into your hard drive. Or you can use TredoSoft's installer which contains IE3 IE4.01 IE5 IE5.5 and IE6.