Following are few useful links:
http://www.buildwindows.com/
Below article has good FAQ and some clarity on Windows 8:
http://stevesmithblog.com/blog/analyzing-windows-8-and-winrt/
Windows 8 Developer Preview download: http://msdn.microsoft.com/en-us/windows/apps/br229516
Visual Studio 2011 Developer Preview download: http://msdn.microsoft.com/en-US/vstudio/hh127353