I created a dual boot system by adding a second SATA internal drive to my Mac G5 Quad. In system preferences you can highlight which drive you want to start up with, or if I remember correctly you hold doen the option key as you start your system, and then you can choose which drive to use.
I put an identical OS on each drive, but in my case I have Media 100 Hde on one drive and FCP on the other. It works great! The concept isto avoid conflicts with programs and drivers by using two drives. Hope that helps.