not supported by boot camp, but it might be possible to put a new HD in your comp, install OS X, boot camp, and Windows, then transfer the HD to an external enclosure and boot XP from it. I have no idea if that would actually work, but its the only way I can see it being done. ...or possibly could use the external drive to boot your computer into OS X install boot camp and it might fool the computer into thinking that the drive you booted from was an internal drive. OK thats it for ideas, tell me if any of them work, im interested now.