Asus will release a Windows 8 version of the Prime about 1-3 months after the first. The first version will not run Windows 8 without third-party dev work.
Yes, Windows 8 will have an ARM version.
No, Microsoft has said not to expect Office and other regular apps to work on ARM Windows 8. Only Windows 8 "Metro style" apps should be expected to work.
Yes, but then at BUILD they said it was only a "technology demonstration", that the ARM version of Windows will only run "metro style" applications, not desktop apps like Office.At CES MS demoed Win8 on ARM running Word & Power Point.
http://www.youtube.com/watch?v=lRPh4kJpeSA