thats how I have my xbox360 conencted. its on the same home LAN or SoHo (small office / home office)
network. basically get a network switch or plug them in the same router. All my music is on my Media center pc and I can play it while playing games on the 360. Also with this 3vix plugin it also is able to stream music in my itunes library along with whats in the windows media player library.
