There is a free beta Sonos controller in the Android market called Andronos. Not used it, but the comments seem generally positive.
US firm Sonos first debuted its first products back in 2006, and it offered just about the best example of a self-contained, multi-zone wireless music system that had yet been seen. It featured an iPod-like hand-held controller and used the company's proprietary wireless technology – rather than Wi-Fi – to connect your PC to a …
...Is that you have to scroll through everthing by name alphabetically and you normally give up by the letter C. I have over 1200 albums on the Sonos and browsing through the collection is such a drag. It's easier to look at the CD boxes themselves. Much as it pains me to say so, an ipod-type-coverflow-type-thing would make browsing a lot easier. Even Windows Media Player 11 is easier to browse through with a search bar and browsing by album cover.
.. but also under half the functionality. The BU250 includes a CR200 controller and two ZonePlayers (one with amplifier, one without), but an S5 and ZoneBridge for £429 is only one zone and no controller. Makes the price comparison a bit daft.
I should add that I'm a very happy Sonos user, but I'm unlikely to add one of these as an extra zone.
If you're wiring it in to your network it's a cheap option. The S5 is less than a ZP120 and that's also before adding speakers. If you do not have a iPhone or iPod Touch, then you can still control it through your PC/Mac.
I got a BU150 set in the Richer Sounds sale (when the new controller and BU250 bundle came out) and added a S5 as a third zone which was both cheaper and more practical. I can move it around the house and the only limitation is the need for a power cable, no having to move speakers (or even stereo system/amp) around.