A receiving and converting device from Yamaha (two models: TRX-T10 and TRX-R10) can turn the power lines in your home into data transmission lines (without affecting the current). As shown in the figure, you can connect your home surround sound system with a few converters. This way, you can conveniently connect each speaker using your existing resources, and you won't have to worry about wiring troubles. For more pictures, look here.