^^^^Actually, that's not quite true. The 2008 (3,1) Mac pro Optical Drive interface is Ultra ATA/100 not SATA as in later Mac Pros. I don't think you can find a DVD with that interface today. You may need something like this:
http://www.amazon.com/PATA-SATA-Serial-Converter-Adapter/dp/B001MW926I
Also, my recent experiences with Pioneer Optical Drives have been very poor.
Lou