So I just talked to Andy about his article here and his sources sound solid. If this is true, it’s a blockbuster:

Publicly, Microsoft has said Windows 7, the successor operating system to the firm's much maligned Windows Vista, will not ship until early 2010, but its internal calendar has June 3, 2009 as the planned release date, InternetNews.com has learned.

Also, Microsoft will use its Professional Developer's Conference in late October as the launch platform for the first public beta of Windows 7. Microsoft plans to release the first beta on October 27, the first day of the show, when Chief Software Architect Ray Ozzie will be the keynote speaker.

Microsoft has what are called Milestone builds and is believed to be on its third major build, called M3, before releasing the beta.

This much is known about Windows 7: development is being led by Steve Sinofsky, who led development of the very successful Office 2007. Windows 7 is not a whole new OS but an evolution of Vista, and will reuse the old kernel and device driver model. That means it would use the kernel in its newer state, when Microsoft updated it with Vista's first service pack. It also means existing device drivers for Vista will work on Windows 7.