I'm having a similar issue, too. I have a wireless N connection to computer, router, then a wireless N bridge to my PS3. I stream a movie, the video is fine, streams at 8-10Mbits/sec, but the audio is constantly dropping out, starts high at 200kbps/sec, but over the course of about 5-10 sec, it slowly drops to 0, then jumps to 15-20kbs and plays, then stutters out again. connection is fine because video seems to stream ok. I also can't play any mp3/audio streaming, which is not bandwidth intensive.
This also happened while I was completely hardwired. I've tried all differnt codecs and bitrates, and all the same problem. Anyone else have this happen?