OK, I can't figure out what the hell is going on, but I can't seem to get my PS3 and my PC to see each other. The PS3 is online, and I can ping the IP address, but it won't show as a device in Media Player when I try to setup sharing. I have configured my router to enable plug n play, but that's it. Do I need to modify anything else with the router?
OK, so I dumped Media Player and installed http://www.twonkymedia.com/. Worked like a charm! This is some good media sharing shit. Streaming 3000+ tunes right to my stereo system is fucking sweet!