AirPlay is a very cool technology, but it's limited to the second generation Apple TV and a few receivers. Sonos, as I reported last week, has come up with its own way to integrate AirPlay into a multi-room music system, and the company was nice enough to lend me an Apple AirPort Express to try it out.
Since I already had a Sonos music system, the AirPort Express was the only missing piece. You plug AirPort Express in, connect it to one of your Sonos ZonePlayers with an Ethernet cable, and run a stereo mini-plug to stereo RCA cable from the AirPort Express to your Sonos unit.
From there, you open the AirPort Utility (it ships with OS X, and you can download a Windows version) and configure it in a couple of easy steps. You then move to your updated free ZonePlayer software version 3.4 to let the Sonos system know that the AirPort Express is there. That's it.
From that point on you can wirelessly stream audio from your iPhone, iPod touch or iPad into your Sonos system. The Sonos is smart enough to auto switch to the correct input, and then you can hear the music on any individual ZonePlayer or on all of them at the same time. Of course, since the playlists on my iPhone and iPad are subsets of the music that Sonos normally has access to from my Mac, there's not much advantage there. On the other hand, I went out running yesterday listening to a podcast, and when I got back to the house, I was just a couple of taps away from hearing it on any or every audio system I had in the house. When the audio switched, not even a word was dropped.