GameSpot has a story up about a survey conducted by Greensfield Online. Apparently it contained some questions for consumers about concepts for new Microsoft products. One such product was an Xbox connection kit, which would let Xbox owners connect their systems to a PC for the purpose of accessing MP3s and other files. Apparently the connection would be made via ethernet
Like anything else like this, take the mention with a grain or two of salt-- last time I read anything about it, the audio files in the Xbox were Windows Media Player files and not MP3s.