I am looking into buying Virtual PC for my PB... i am looking in the mac store and i notice many different ones to choose from... Virtual PC with windows XP, Virtual PC with DOS... i was wondering... when would you use the virtual PC with DOS??? Anyone use Virtual PC with Windows XP? Also what is the Virtual PC 6.0 upgrade? Do you need to buy that when you buy Virtual PC 6.0 with Windows XP? Thanks!