I thought saw Microsoft virtual machines for testing IE previously, but you probably had to be an MSDN member. Now it appears they’re ripe and ready for everyone. Yikes, they’re huge downloads! IE10 on Win8 is 2.5Gb, IE9 on Win7 is 4.7Gb!
I wanna say I’ve of BrowserStack before, but looking at the site didn’t jog any memories. Looks like a pretty good service too.