I was wondering if it is possible to install unix on a winxp cpu and not mess up the xp o/s
Absolutely. And I think you mean an intel or AMD cpu, because XP is just the OS. You can do a search on this forum and google for dual booting. You need to choose a flavor of *nix. You can find more info in the FAQ section of this forum.
Dual booting is very easy to configure providing that you install Windoze firstly, and then put the *nix on there secondly, otherwise Bill comes along and trashes your boot loader. If your partitions are NTFS, you will need a fairly modern Linux distro to resize them. If they're FAT32 you won't have such a problem.
I used to have a laptop dual booting Win XP and Linux. I found myself using Win XP less and less and then finally got rid of it. That was almost two years back! The onlyplace I use Windows is at work because I administer a heterogenous Linux/HP-UX/Windows network. If I were our IT Manager, the final OS in the list wouldn't be around, but that's beyond the scope of the forum 
!!
Cheers
ZB