Answer:
What are you trying to accomplish with it? Do you want a bootable CD to run an instance of XP as in an operating system? or do you want to re-install XP?
Bart PE is a CD you can use to give you a very light version of an XP OS but it's only to fix or test programs with in an evironment. Its really a tool to help repair a pre existing installation. (you need a real product key to create a custom Bart PE CD)
If you want to re-install the XP OS on a hard drive, legitimate XP CD's are already bootable.