I just tried out http://www.browserstack.com/ for testing my minimal IE8/IE9 changes for Nice to have. It's actually really quite handy. Take my review below with a pinch of salt though, as I only used it for 30 mins. I did a free registration around xmas and forgot about it, so that's all I had left today! Silly mike.
All the standard debugging tools are set up (e.g. firebug lite), and you get a single window to play in. You set up a tunnel through a signed app so that it sees your server, choose your OS/browse combo, and your off. You do your edits locally, as normal, using whatever libraries and editor you fancy. It is a bit laggy, but usable, and that could have been my connection to blame.
It's around £12 ($19) dollars a month. Given I can set up a VM locally for IE testing if I really need to, that's not in the range where I'd immediately upgrade to paid, but I'll definitely consider it next time I'm doing a bunch of IE testing.