SP2 introduced a completely different software to XP - which made Boot Camp workable. SP1 is inadequate for Boot Camp.
That said - someone here figured out a way to install SP1. This was a technological miracle - and it seems to be as fun as do-it-yourself dentistry.
Your real answer is to:
a.) download a free SP2 update and slipstream it with your own XP-SP1 into a fresh install disk (LOTS of work)
http://www.winsupersite.com/showcase/windowsxpsp2slipstream.asp
or
b.) purchase an OEM XP-SP2 disk. This is a disk MUCH cheaper than the usual MS boxed product. It has no package, it has no phone support, it is "tied" permanently to the machine it is first installed to.
EDIT - don't try the SP1 even as an experiment, it tends to "get stuck" and freeze your Mac rendering it totally useless
Message was edited by: NA Smith