Testing your site in the various different flavours of browser is by far one of the most tedious and hit or miss experiences every web developer will face.  This is probably truer of IE than most.  The only real way to test properly is to have multiple machines (or VMs) with original installs of each version.

For quick testing as you develop however, wouldn’t it be great if you had a desktop app that emulated all the different versions?  Well this is what IETester claims to do.  I’ll admit that I’ve not tested it a lot, but a quick browse through some sites that I know have IE 5.5 issues seems to suggest it’s doing it’s job.  IETester claims to emulate not only the rendering engines of IE8 beta 1, IE7, IE6 and IE5.5 but also their JavaScript engines.  It’s currently only in Alpha but if they manage to pull of what they’re claiming this is a killer web dev tool.

On a similar theme another impressive, but slightly less useful testing tool can be found in http://browsershots.org/ - given a URL it will produce screenshots of the site on a dizzying number of browser versions and platforms.  There’s no emulation here, but rather a network of physical machines each installed with a different browser version.  Whilst impressive, it has drawbacks; you only get a screenshot of one page in your site, that page has to be public and it can take a while to process.  It’s still a cool project though.