Wanna switch to Windows 7 before the full version comes out, but don't want to pay for the upgrade? No problem—just stick with the release candidate for a while. PC World reports that licenses for Windows 7 RC1 won't expire until June 2010.
That's a considerably longer testing period than what Microsoft allowed with Vista. The second Vista release candidate came out in early October 2006 and expired on June 1, 2007, just eight months later. (If you're too lazy to do the math in your head, the Windows 7 RC will be usable for a cool 13 months.)
Windows 7 RC1 already came out for TechNet and MSDN subscribers yesterday, although PC World says eager testers quickly overloaded download sites. The public release is still on track for May 5. Microsoft hasn't officially talked about caps on public distribution, but a leaked page that popped up last month reportedly mentioned unlimited product keys.
Windows 7 RC1 won't have all the spit and polish of the retail-boxed version, of course—but it may not be too far off. PC World goes on to say that Microsoft doesn't plan to churn out a second release candidate. Instead, the company will move straight to the release-to-manufacturing stage, with a retail launch to follow shortly thereafter.
Update 05/03: The source article left out an important detail: Windows 7 RC installs will begin shutting down every two hours starting on March 1, 2010. (Thanks to TR reader Jeffrey for the heads-up.)