It's only via the official channels, subject to the translucent filtering of Steven Sinofsky, senior vice president, Windows and Windows Live Engineering Group, that Microsoft is pointing to a period of time by the end of January 2010 as being the general availability of Windows 7. In contrast, unofficial indications, as well as the crumbs that slip through the Win7 GA feats, deliver a launch date ahead of the end of 2009. In fact, Microsoft itself is offering confirmation that Windows 7 could drop as early as July 1, 2009.
In mid-October 2008 via a job posting for the position of Sr. Controller, Windows Client - Financial Analysis & Controls, the Redmond company indicated that Windows 7 was planning for release in FY2010.

According to the posting, the SR. Controller would have to “Lead the planning and reporting cycle for the growing Windows Client business with $16B in annual revenues, as we deliver on the potential of Windows Vista and the anticipated release of Windows 7 in FY10. Help make an impact on the 800 million customers across the globe who use our products in their daily lives.” (emphasis added)

Microsoft's 2010 fiscal year does not correspond to 2010. Instead, FY2010 starts on July 1, 2009, and comes to an end on June 30, 2010. Of course, the official release date provided by Microsoft falls within FY2010, and in this sense Windows 7 could also be offered as late as June 30, 2010. But, at the same time, a FY2010 delivery date reinforces the possibility that Windows 7's general availability date will be by the end of 2009.

Sinofsky revealed that Microsoft planned to deliver a single Beta of Windows 7, and then to move straight to Release Candidate stage, from which to evolve directly into RTM. And the fact of the matter is that Windows 7 has been already reported to be released to manufacturing in mid-2009, just to make it on store shelves, both real and virtual, and pre-loaded on OEM machines ahead of the 2009 holiday season.