Plex has announced that their service can be linked to your Sonos speakers.
Plex for Sonos | Media Server | Media Streaming Server:
Plex can connect to any Sonos system wirelessly, no matter where it is. You always have access to every one of your songs, playlists, and music libraries with Plex.
I use Plex to host and stream my video and music library. I also just bought my second Sonos speaker for the living room in my house. I must say that I am thrilled that I will now be able to stream anything from my Plex library to my Sonos speakers.
If you are curious about setting up a free Plex account, it is easy to learn about from their website. Did I mention that you can read about how I use Plex in my forthcoming book, Digital Organization Tips for Music Teachers? You can preorder that here.