You really dont need to care. The Northbridge ans south brige are just chipsets that control stuff.
The North is for the CPU, memory and AGP. The south is everything else. It is the integrated circuit that controls the PCI, USB, Serial, IDE, ... and the list goes on.
Your South is made by VIA as is stated in the description of the board if you go to the asus site.
You should have recieved a CD in the box that will contain the drivers for this.
Boot the machine with you XP cd, press F^ when you see the prompt. The machine will continue on and you will be promopted for the CD for this. Insert it and find the drivers you need. It's not too tough.
Problem is that before this will work, you need to configure the RAID to see the HDD. This involves setting the BIOS so that you have the SATA raid controlers turned on. Then you need to enter the bios config so you can setup the drive. You might also need to change the boot order to allow for the SATA controller to have a turn...
