Stephan Chapman from Microsoft Kitchen published some thoughts & pictures from roadmaps about the further development of the Microsoft Windows Operating Systems. It seems, that Windows 8 could be RTM in 2012.
It seems that the next major OS from Microsoft will also include Hyper-V as a part of the Operating System Kernel.

on Stephan Chapmans post he wrote:

Well, on this day of PDC 2009, since I won’t hear anything about Windows 8, I took it upon myself to see what I could scrounge up. It looks like a bit more is being announced to partners where Windows 8 Server is concerned… well, in the context of a roadmap, at least. The information all says the same thing I’ve been reporting via other roadmaps: Windows 8 being released around a time frame of 2012. Perhaps the whole, “end-of-the-world” thing in 2012 really has something to do with Windows 8. Or not. lol.