We still need IE6 compatible sites and refusing to make your commercial sites IE6 compatible because "everyone should upgrade” is like driving around screaming at the other drivers - it serves no purpose other than to hear yourself screaming.
The sad fact is that many potential site visitors are stuck in a rut with IE6 for one reason or another - but the clients (you know, the people who pay us?) still want us to reach every possible potential customer in spite of the level of their technical prowess. Therefore, we have to continue to test in IE6 an make sites comply.
IETesterdoes this task for you. You can run this software under Xp/Vista and can run 4 Different versions[IE8, IE7 IE 6 and IE5.5] of Internet Explorer without messing anything around, as well as the installed IE in the same process.
Below is a screenshot of how it looks when running: