Some useful info on Airplay...
Apple’s new streaming technology, AirPlay®, launched on Sep 10, 2010 as an update to the now defunct AirTunes. AirPlay lets you stream all types of media—music, video, photos— from any iOS device to any AirPlay speaker system. All you need is a basic wi-fi connection. This puts AirPlay up against the venerable Bluetooth streaming technology and we set out to learn the differences between the two technologies.
AirPlay – More Listening Freedom
Bluetooth requires speakers to be within 32 feet of the audio source, AirPlay requires only that source and speakers are connected to the same wi-fi network. This means you could have your iTunes library connected to a computer in your bedroom and be able to play its content through speakers a couple of floors away using AirPlay. As long as the two devices are on the same network, AirPlay will let you stream audio from one to the other. AirPlay also permits audio streaming to several devices simultaneously from one dedicated audio hub.
AirPlay – High Fidelity Audio
Bluetooth cannot support uncompressed CD-quality audio over its network. AirPlay can. It can transmit lossless audio from content source to speaker, so music is reproduced with the highest possible fidelity.
AirPlay – More media; more information
AirPlay can stream song titles, artist names or even volume settings of the source device. This functionality does not exist in Bluetooth streaming.