I am coming from a MacBook Pro with one physical drive.
You can't control the size of the partition that XP is installed on under XP. This is more important if you are using Boot Camp on a laptop since most laptops only have one physical drive installed.
Example, under boot camp you give 100GB to your XP partition XP will see 100 GB as drive C. This is your main drive and it's where the OS is going to be installed. You can't repartition this drive in XP to make it (2) 50GB drives, (3) 25GB drives etc. This would be a better solution for CS3 since one of the logical drives could be used for scratch. You also can't use tools like partition magic to size on the fly or use Drive Image to back up since neither of these tools understand how the Boot Camp positioning works. Thus if you try to back up and reinstall your image, it won't know where to put it. So you can't do anything with that boot camp created partition except use it to load XP/Vista etc and load everything else on. It's very limiting. I have only loaded Boot Camp on Macbook Pro's never a Mac Tower with multiple Physical hard drives. I am not sure if Disk Manager will see other physical drives, but you still won't be able to logically repartition the drive that the OS is installed on.
I never figured out how while at setup of boot camp to create 3 drives, one for OSX, one for the XP OS, and one for Data. There was some info on it, but I never could get it to work and have XP install correctly.
Under XP this is not very efficient. You will have to degfrag this drive and doing it will take considerable time. Also under CS3, you will have to use this same drive for scratch unless you mount an external drive.