phling!
phling! is a new mobile service that lets you tune in to the music stored on your computer (PC only for the time being) from wherever you are. To use it you download applications to both your mobile phone and your PC. So long as the PC is turned on and connected to the internet you can stream your music files to your phone. phling! mediates all of the inconsistencies of the wireless network to ensure even playback. And they also offer a few stations of free internet radio.
Where the service gets more interesting is that you can see other phling! users—people also listening to the same song as you, others online with similar taste or people fitting whatever profile you're looking for. Once you connect with other users you can also listen to their music.
