Microsoft has been mostly tight-lipped about Windows 7, but more and more we are seeing how the company is changing its secrecy stance and starts to build up interest in its next-gen operating system. Last month they launched the Engineering Windows 7 blog, and while no major details have been revealed thus far, Microsoft’s Steven Sinofsky did promise to share “in-depth technical information” at the Professional Developers Conference next month.

Well, it appears that Microsoft is well on track with the development of Windows 7, as today the company greeted the developer crowd with news that keynote attendees will be among the first to receive the pre-beta build of the OS. There is still no official word on when a public beta of Windows 7 will be shipped. Microsoft has said it plans to ship the final version in early 2010, though recent rumors claim that the company’s internal calendar puts the release date as early as mid-2009.