<A href="http://www.extremetech.com/computing/117771-windows-8-on-arm-kills-the-windows-software-ecosystem" target="_blank">Microsoft's Steven Sinofksy has written an explanation of the Win8-on-ARM position</A>. Win8 on X86/64 and Win8 on ARM (WOA) will ship at about the same time but will be very different. Applications from one platform will apparently not run on the other.