After following Total-MAdMaN's instructions you can then use any of the standard partition tools (fdisk, Gparted, etc) to remove the unwanted Linux partition(s).
If you no longer have the the XP CD, you can also restore the MBR using the install-mbr utility found on Knoppix, and perhaps other, live CDs.
EDIT: Apologies ... The previous post wasn't showing when I started.
Last edited by blackhole54; 10-01-2008 at 06:59 PM.