Although there was an older solution on xlr8yourmac for using an external FireWire DVD drive in OS X, it no longer works in 10.2. In fact, 10.2 doesn't even install the Apple DVD Player if you have an external FireWire DVD drive. This solution was originally found on Macslash, but didn't work entirely, and could have been made a little clearer. No longer must external DVD drive users be stuck with VideoLAN Client :)
For clarification, I did this on a Powermac G4 with a generic IDE DVD drive put into a Firewire enclosure.
Mac OS X Hints
http://hints.macworld.com/article.php?story=2002121704462629