When you install Leopard use the menu item to find "Disk Utility" (before you go to far during the install process). . Launch it and let it find the Firewire hard disk. Then highlight that drive and in the right hand pane select 'Partition". In the Partition pane select 1 Partition and then look near the bottom and select 'Options'. A drop down will come to format the drive to make os install on either PPC Mac or Intel Mac (it will tell which one you want). You must do this to make the drive a bootable drive to install OS X on.
Mac Pro Dual 2.8 Quad (2nd gen), 14G Ram, Two DVD-RW Drives, OS X 10.8.3
2006 Mac Book Pro 2.16 (first Gen) OS X 10.7.4
2TB Time Capsule, 2 TB
32G iPhone 4S Black, iPad (3rd Gen) 32G Black