Go browse and search through some of the posts at linuxnewbie.org and they have some good pages on general stuff too. RedHat and XP are pretty common to have on a dulaboot machine, so I know it's possible. Personally, I have redhat on two different machines, but they are only linux. There are many help pages on the net about making dualboot machines, perhaps you should search google for some to read up on it. There is probably a way to install redhat on your system without having to reinstall XP.
BTW, RedHat 8.0 was released today.
