If you have a plain IDE Hard Drive, then yes, it will work. All IDE HD's work with just about any motherboard. Also, yes you will need to reinstall XP. Some people have been able to start up with the new config, and just repair the installation, but I've tried it and it never has worked.
Current Build (Hope to finish by late spring):
Intel Q6600 g0
Asus Maximus Formula
geIL Evo 2GB (2x1gb) DDR2
ATI HD3870 X2 or Nvidia 9800 X2?
2x 150gb RaptorX (Have it)
Thermaltake Toughpower 750w PSU (Have it)
Antec P182 Case
HP w2207 22" Monitor (Have it)