Microsoft unveiled there won't be any additional Windows 7 beta versions, the operating system will skip straight to the release candidate stage. If everything goes well, Windows 7 should be available before the holiday season.
Windows Engineering Senior VP Steven Sinofsky states plainly, "The next milestone for the development of Windows 7 is the Release Candidate," although he notes out that his post "is in no way an announcement of a ship date, change in plans, or change in our previously described process." Indeed, Microsoft purportedly told partners about its plans for a single beta at the Professional Developers Conference last year.
Right now, Microsoft is sifting through user feedback and focusing heavily on "quality and performance," which should help get Windows 7 to a "known shippable state"—that's the RC build. The release candidate will be provided as a refresh for the beta, and Sinofsky expects a "broad set of folks to be pretty interested in trying it out." (His post doesn't specify whether the RC will get a public release.)