You might want to stay away from that one...
Hi James,
You are looking at a Digital Audio (the series included the 466, 533, dp 533 667 and 773 mhz machines). This replaced the venerable Sawtooth series and unfortunately they also added some 'new' features... one of these being ADC (the Apple display connector used to power Apple's LCD's). When this occured the power supply was changed from a standard 20 pin ATX to a 22 pin proprietary with the additional pins supplying power to the ADC ports on the Logic Board. Without some step up voltage converters you cannot use a PC ATX PSU on the digital audio board (you can use an ATX PSU on the Sawtooth generation).
When Apple then went to the Quicksilver line (733, 867, 933 and DP1G) they also added 4 more pins to a secondary connector which is used for the higher draw of the newer processors. You can, however, use a Quicksilver supply to power a Digital Audio by not hooking up the 4 pin connector (letting it float) and disconnecting the purple wire (I would have to go read to find out which pin that is) out of the 22 pin connector.
So your options are a Digital Audio PSU or a Quicksilver PSU, both of which are not cheap. Count on ~ $200 used from an online retailer or take your chances on Ebay for ~$100+. This is just to get you started, the Logic Board may be kaputt leaving you with a door stop.
Best,
Rob