Utilu IE Collection
This works. Goodbye and good riddance, three IE-dedicated VMs.
IETester
A "free browser that allows you to have the rendering and javascript engines of IE8 beta 1, IE7, IE6, and IE5.5 on Vista and XP, as well as the installed IE in the same process."
Microsoft: Internet Explorer Developer Toolbar
Invaluable for troubleshooting web development in IE. Wish I'd known about this before today!
funkatron.com : Assumptions and Mac browser share
Firefox has more users, perhaps, than is commonly assumed. With Firefox 3 on the near horizon, this may shoot up even more.