I run XP on my machines, so here's what I did:

I downloaded the free (and legal) Microsoft Windows 7 enterprise trial ISO:

http://wb.dlservice.microsoft.com/dl/download/release/Win7/3...

I installed the free VMWare Player (actually I already had it but needed to update to support Windows 7 more natively)

http://download3.vmware.com/software/vmplayer/VMware-player-... ( or http://www.vmware.com/download/player/download.html )

I used one of the free vmx generator tools to make an image ready for Windows 7 and set the ISO as the CD drive

http://www.easyvmx.com/supersimple.shtml

Installed in less than 30 minutes (including VMWare stuff) and then I can test in a pure Windows 7 default environment.

The great thing about the Enterprise trial is it lasts for 60 days, then you can "rearm" (google it) for a couple more times, but even when it's expired, you can use it for an hour before auto-shutdown which is plenty of time to test pages.

Keep an eye on IETester: http://www.my-debugbar.com/wiki/IETester/HomePage

Right now they just have IE9 beta, but I'd imagine they'll have full IE9 support soon.