Microsoft has opened up the “release candidate” of Windows Vista for public testing. This page has program details and download guidance.
If you’re the right person to test Vista, then you don’t need me to tell you so. If you have to ask, then you shouldn’t go anywhere near this test. It’s the most stable version of Vista yet and many testers are impressed and happy. But if you put it on a computer that you expect to be stable, or if you upgrade a functioning computer, then you are making a terrible, terrible mistake.
I’ll test it, I hope, but my platform will be a brand new computer with a hard drive that I will reformat during the installation. I fully expect to be reformatting that drive a few more times before I’m done. If you’re not ready to do that, then you should treat Vista testing as a spectator sport.