Here is a picture of the adapters necessary for an internal SCSI CD-ROM:
http://benboldt.spymac.com/cd-rom/internal-back.jpg
You will also need to attach a 5.25" bay sled to the bottom of the drive as seen here:
http://benboldt.spymac.com/cd-rom/internal-sled.jpg
If you get an external SCSI enclosure to put the drive into, you will only need a common SCSI cable and terminator as seen here:
http://benboldt.spymac.com/cd-rom/external.jpg
All the other connections (SCSI, Power, Audio) will be provided by the bay. You could probably just buy a whole external SCSI CD-ROM already put together for the same price, though. I can't imagine they're too expensive.