google search, or search here for dual booting linux and winXP. very easy to do.
1. install winXP with the C: partition being what ever size you want.
2. during winXP install create but do not format a D: partition during install.
3. once XP is up and running and you are happy with it right click my computer, manage, format the new partition FAT32 (as long as it is under 132G, if it is over, ignore it and skip this step.)
4. install Linux distro of choice.
5. when prompted by grub to setup a dual boot do so and choose what OS you want as the main OS. windows of XP.
you are done.