Testing Multiple Versions of IE on any Platform

The best summary of the available options I've found is the article, "Reliable Cross-Browser Testing, Part 1: Internet Explorer". The upshot is that if you want to engage in the article titular activity, you'll be relying on VMs. Having used the other approaches outlined in the article, including Multiple IEs, I have to concur with this conclusion and aver that it is ultimately the only approach that provides the flexibility you'll need when you you need to debug some odd CSS or JavaScript behavior in IE6 with some odd configuration.

So, the real trick is minimizing the pain of getting this setup. If you are running on Linux or Mac OSX, you'll be happy to find out that you're a shell script away (almost). This script uses Oracle's Virtual Box to operate the VPC images. It is ironic that this is the only way that Windows 7 Home/Home Premium users can use these images, since Virtual PC and the XP Mode feature are not available without the Pro or Ultimate SKUs.*

Once you've got the IE App Compat images downloaded, you'll likely find they have a couple little problems: BSOD on boot and Windows activation; you'll find the solution to those problems in this blog article.

* As an aside, how long do you think Microsoft will continue this multiple SKUs? An OSX Lion upgrade is $30--for new VERSION! It doesn't matter, I suppose, given that most folks think Windows 8 will be DOA.