The king of leakage, Wzor has done all Windows users and followers a favor once again as he has released screenshots of Windows 7 post-RTM screenshots. Stephen Chapman of MSFT Kitchen believes that this could  officially mark the beginning of the Windows 8 development. Leaked screenshots has the build number 7700.winmain.100122-1900.

windows7postRTM

This is why this could be the beginning of Windows 8 development:

Microsoft typically keeps the current version of Windows tagging in the early builds of the next version. The build string usually changes to reflect the next version prior to anything else

And to further strengthen the claim the Beta fish wallpaper is back as you can see from the screenshots here. Here is explanation of the build number 7700.winmain.100122-1900, where 7700 is the build number, winmain is the lab in which this build was compiled, 1900 (7:00 PM) reflects the military time 100122, is the date written in the format yyyy/mm/dd.

You may want to check out the following links:

Windows 8 coming your way on 1st July 2011

Screenshots of Windows 7 SP1 Beta leak out

How to: Hide drives in Windows 7 the easy way

How To: Enable Windows 7 Secret God Mode

Aero calculator : The transparent calculator for Windows 7