I have a reformatted Mac mini containing only a fresh install of Ubuntu 9.0.4. The Apple boot loader as been removed, so I can't hold down option, or the c key to get it to reboot form the install DVD. I do have an external drive (with both a usb and firewire interface available) with a bootable cloned OS X system on it.
What steps do I need to go through to in order get grub to see the external drive, and to boot from it so that I can reformat the internal disk as an OS X drive?