Run Multiple Internet Explorer Versions on Windows
I use VMware Fusion just to run Windows so I can test my sites on Internet Explorer.
I have just installed IETester which allows you to run multiple versions of this browser on your host system, all from within a single window. It saves me having to go backwards and forwards between my Mac, Fusion (that previously had IE7 on it) a PC with version 6 on it and another with IE8.
Here’s the link: IETester download.other page