parallels runs in software mode and can be in a window or full screen (I have two screens so one is XP and t'other is Mac OSX). Parallels software is still developing but it seems to work very well.
Do not compare it to Virtual PC.
It's nothing like it - its faster and you can install normal PC software in it etc.
Check the forums at forums.parallels.com for info.
Blimey, I should be on commission for Parallels...
