Even though it has already been rumored that the near-final Windows 7 RC will be ready for testers in April, and the public at large by May, a recent leak coming from Microsoft's own website has all but confirmed this information. Apparently, someone jumped the gun over at Redmond and posted the download page a bit early onto TechNet.
The document was pulled shortly thereafter but not before the information it contained made its way onto several websites. Specifically, it indicates the Windows 7 release candidate is due to be published in May 2009, it will be at least available through June 2009 with no product key limitation, and will expire on June 1 2010. It also details hardware requirements for the release, which are still the same as those for the beta.
By now it is probably safe to assume Microsoft will indeed deliver Windows 7 in its final form before the end of the year - it's just a question of exactly when. A launch around August or September seems right for the company to perhaps catch some back-to-school sales and build up their marketing efforts into the fourth quarter.