I'm a little bit in the dark on SCSI, but I believe plain SCSI is 8-bits wide, and wide SCSI (ultra wide for you) is 16-bits wide. There are also SCSI, SCSI-2, and SCSI 3, all of which come in narrow and wide formats.
If it is just plain SCSI, you should be able to pick up a card fairly cheap: ~$50 USD for an Adaptec SCSI controller. This will be for a 50-pin drive---which look very similar to IDE connectors--but you'll have some extra room if you try to plug in an IDE ribbon cable (I know this first hand). If it's the newer 68-pin SCSI, you'll have to look into something a little more expensive: ~$150-200USD.

If that doesn't answer your questions, you might wanna head over to 2CPU and hit the Storage section of the forums. There are some FAQ's that might help you there. If you are still running into problems, get ahold of Upabevoit---he really knows his stuff when it comes to all things SCSI.

Good luck.