If you run Parallels for Mac (assuming it's an Intel Mac), it has a "transporter" that will copy XP files/config/etc to the Parallels image.
I run Mac's 95% of the time, but run XP Pro at the same time (not different boots), to do Windows Terminal Services and VPN stuff.
By far the best solution I've ever seen, and the performance is incredible...
http://www.parallels.com/en/products/desktop/
Best $80 I ever spent.
$0.02