Windows 8 may have already passed Milestone 2, according to the Russian forum Winreview. Microsoft is thus currently working on Windows 8 Milestone 3, which will likely be compiled in the next few months. For those following the build numbers, builds 78XX are reportedly under the Windows 8 Milestone 1 branch while builds 79XX are under Windows 8 Milestone 2:
Windows 7 Post-RTM: 6.1.77xx.0.winmain.xxxxxx-xxxx
Windows 8 Milestone 1: ?6.2.78xx.0.winmain_win8m1.xxxxxx-xxxx
Windows 8 Milestone 2: 6.2.79xx.0.winmain_win8m2.xxxxxx-xxxx

Microsoft is working hard on the successor to Windows 7, but the operating system is still in very early in development. The software giant hasn't even announced Windows 8 yet, though we do know it is coming sometime next year. All that we currently have to go on are rumors and leaks.

Leaked documents have mentioned support for USB 3.0, Bluetooth 3.0, facial recognition, stereoscopic 3D, instant on booting, HID, accelerometers, proximity sensors, hard drive encryption, GPS integration, as well as a strong focus on boot time, shut down time, and battery life. Rumors have included two user interfaces, a renewed push in PC gaming, and a sneak peek at CES 2011.