AirPlay works with iPhone, iPod Touch and iPad devices with iOS 4.3.3 or later, Mac with OS X Mountain Lion, or Mac and PC with iTunes 10.2.2 or later.
Any device with Bluetooth functionality should be compatible for connecting to the Air via Bluetooth.
You can also connect any device with either a 3.5mm or RCA phono output to the analogue input on the Air. For example, you can connect a TV or MP3 player to the analogue input to play that audio through the Air speaker. The analogue input is selected by pressing the X button on the top of the Air.