I know this is probably a move by the lawyers, and the browser-promotion folks probably don't even know about it yet, but seriously... If you want to promote your (free!) browser, you have to make life easy for developers.
It appears as if the IE exe's made by Xenocode still work. I don't have a link for them, I'm not sure if they're hosted anywhere still.
You may also want to check out http://shapeshed.com/journal/testing_with_ie6_ie7_and_ie8_on... if you wish to use virtualbox rather than paying for virtual PC
Anything Microsoft does to accelerate their own obsolescence should be encouraged.