creating RAID

I'm aiming to raid mirror two SATA drives when I build my pc tomorrow night and wondered if I have to setup RAID 1 in the bios first before I install windows XP? and will XP recognize RAID in the setup? or do i need a disc? asus supplied me with a support cd but not raid disc.

On the Asus cd it has the raid drivers, make a floppy, and when you start the setup press i think f6 to install the drivers.