Hi amitcho,
When you're running Windows using Boot Camp you aren't emulating Windows, you're actually running Windows just as if it was on a PC. Although I haven't used Xfrog, I use Vista and Win 7 extensively on my Macs using Boot Camp and haven't had any problems. If Xfrog is known to run fine on a PC running Win 7 then I would say it would work just as well on your Mac using Boot Camp.
For preference I would rather use Win 7 than XP.
Regards,
Jo