Q: Is it possible to network a 360 and a PS3? Would you be able to play GTA4 multiplayer on it? (One copy of GTA is an Australian version (360) and the other a copy from the United States?)
A: If you mean can the PS3 connect to XBox 360 to allow mulitplayer online play then I think the answer is no. I think PS3s can only connect with PS3s and XBox 360s can only connect with XBox 360s.