This one's to our OP (original poster):
Apple isn't going to let Boot Camp support XP on the Thunderbolt iMacs anytime soon. XP, for all its good, is just that old, A decade old, to be precise, as of late October this year.
Vista might have worked, but Apple rightly cut that one off, too.
I've a pending tip re: a quick Boot Camp setup, but it isn't open yet. So, we'll go with the following:
If you really want to run XP, you'll need to set it up inside a virtual machine host. Be prepared to dedicate enough RAM and hard disk space for the task, because the virtual machine (VM) we'll soon set up will take all of what we set up.
First things first: Grab a copy of VirtualBox at http://www.virtualbox.org/ and install it.
Make your VM template with at least these settings:
- Hard disk: 40 GB or larger
- RAM: 1 GB or more
- VT: Enabled
- Physical Address Extension (PAE): On (improves performance some)
- 3D Acceleration: On (needed for most games)
I'll leave it to you whether you want to use multiple CPUs or provide ports to connect your gear to the VM, but at the very least you will need access to the host (Mac OS) DVD drive to get the XP CD running anyway, as well as the host network adapter for updates, etc.
Now that you've set it up, start the VM and install your XP as if it were on a real PC.
As for drivers, have VBox install its Guest Additions software. This should install the emulated hardware drivers as well as software to "connect" host to guest (Windows is the guest here).
Now, install other software as you like. I'll leave this one in your hands.
Good luck,
Nate