First up, do you have a RAID controller or are you using the onboard?
I'd suggest a hardware RAID controller if you can afford it.
First thing would be to backup all your data and store it elsewhere for this process. Next you would create the RAID 1 setup with the hard drives, and most likely create yourself two partitions - one for each OS. This will make it easier when following the guide. Install Windows XP on the first partition and get it up and running sweet, then head on over to the following link for the rest of it:http://apcmag.com/ho...alled_first.htm
Note that if you create two partitions in the beginning, then you won't need to worry about that part in the guide. Also note I haven't actually followed this guide myself, however I can vouch for the credibility of the website as it is an Australian computer magazine that I purchase often.
Have a good read through it first and let me know what you think.