Just to add to the above reply, that dual HD bracket was made ONLY for the rev 2 B&W models. If you have the bracket, the OEM IDE cable should have 2 connectors on it and be relatively short, since the drives were meant to be stacked right on top of each other, and only need a short cable to connect both drives. The IDE connector on the mobo is DIRECTLY across from where the drives sit.
If you have neither of the above, you probably have a rev 1 machine, which do NOT support more than 1 HD connected to the mobo, unless you add a pci controller card......
Lookie here at item #3
http://www.xlr8yourmac.com/G3-ZONE/y...wfeatures.html
for one more way to ascertain for sure which rev your machine is...