I've been looking on the site http://wpf.codeplex.com/ and found the Ribbon control finding my needs. I was wondering if it requires any Office licence things etc. on the machine, or this just needs the toolkit dll.
Does it require Win-7 or is compatible on XP machine as well?
The ribbon doesn't have any dependency on office, it just renders with that style. You're all set with or without office.
As for the other question, it depends on a framework up to the WPF level being installed, whatever OS that is, including XP. Pretty soon, you'll want that to be WPF4 due to the much better font rendering IMO.