Win XP

Why would you want to install a desktop operating system on top of a server operating system?

If you need a virutal desktop, then you should be looking at VMWare.

http://www.vmware.com

You cannot install a desktop operating system on a server either as an "upgrade" or dual boot. Only way to install XP is to repartition hard disk and do a clean install.

Dalton

sounds like you need to dual boot a computer as a lab computer? for sure you could use 3rd party boot utility if you can partion off space for the xp install...i wonder if it just wouldn't work to install xp now and have it create boot.ini that you could later modify to include 2003 os. i would research it at support.microsoft.com
you also will need to get drivers for video, network, sound, scanner, printer etc for XP burn to CD first. does 2003 allow encryption? decrypt any data before repartioning the drive. consider data partition and os partion. consider rescue partion where you can install second 'repair' installation of xp if necessary in future...