How can I reinstall Snow Leopard when my DVD drive is not working?
I have no idea why the FireWire external drive didn't work, but the following did:


I took a neighbors Mac Mini and put it into target disk mode
I connected the Mini to my unit via FireWire
I put the media into the Mac Mini
I booted my unit holding the alt key down
When the list of available boot drives/media showed up, the OS install disk was showing up
I selected the optical drive (from the Mac Mini)
I installed the OS


I have no idea why this would work but my external FireWire optical drive wouldn't. It was incredibly slow but it did get the job done.

Although this is a solution, and maybe something that may be of use to someone else, I still have no idea why the external FireWire optical drive wouldn't work.