Say I have 2 hard drives. Could I install Windows XP SP2 on one and Linux Ubuntu 8.04 LTS on the other?

You should have no problem doing that, but when your computer starts up you have to push the boot menu shortcut (f something, it depend on computer) It should say it on BIOS splash screen. Then you have to select which HD to boot from. If you dont do this the computer will just boot from the primary HD