Boot Camp lets you install Windows XP without moving your Mac data, though you will need to bring your own copy to the table, as Apple Computer does not sell or support Microsoft Windows. Boot Camp will burn a CD of all the required drivers for Windows so you don't have to scrounge around the Internet looking for them.
Run XP natively
Once you’ve completed Boot Camp, simply hold down the option key at startup to choose between Mac OS X and Windows. (That’s the “alt” key for you longtime Windows users.) After starting up, your Mac runs Windows completely natively. Simply restart to come back to Mac.
Boot Camp Resource Centre, where to find out stuff on Boot Camp... This is a pretty good resource for Mac users who have installed and are using Boot Camp. Ready to set up your Mac to run Windows? This page is a collection of all the resources you'll need, and a bunch you'll want. There are two types of resources collected here: troubleshooting articles and opinion pieces culled from MacFixIt and software links from VersionTracker. Bookmark this page, check back often, and we'll get through this together.
Making An XP Full Install Disc From An XP Upgrade Disc. This is a useful blog entry if you have an XP Upgrade Disc which can not be used on its own to install XP on a Mac using Boot Camp.
Install Windows to an external USB drive (without Bootcamp, though it could be risky... Boot Camp requires you to install Windows on an internal drive. Some people have managed to install it on an external drive, but still needed to use Boot Camp and partition their drive. It turns out that it is possible to install Windows to a USB disk without using Bootcamp at all.