This is probably fairly well known, but just in case - the general public can now download Windows 7 RC ( release candidate ). No rush here as the Windows 7 RC will be available through download through at least July 2009.
The Windows 7 RC is pre-release software so I wouldn't install this on a production PC, of course. It expires on June 1, 2010, but I love this statement:
“Starting on March 1, 2010, your PC will begin shutting down every two hours. Windows will notify you two weeks before the bi-hourly shutdowns start.”
You can download Windows 7 RC here, but I recommend checking out the Windows 7 FAQ, here, just to make sure you have your ducks in a row before you attempt the install. The Windows 7 RC FAQ will help answer common questions about downloading and installing Windows 7 RC as well as the risks involved in installing it.
Again, I would install this on a non-production PC like I did that had no real data on it. Make sure you backup any data. Quite frankly I don't use the PC that I installed Windows 7 on other than playing with Windows 7, reading the occasional email, and surfing the web.
Good luck!
David Hayden