Let the hive mind of Engadget get that for you.
"I am looking for a device that will stream sound from one source to several recipients. For example, I want to stream sound from my TV or stereo to my phone or MP3 player that has radio and Bluetooth capabilities. I have looked into radio transmitters and they seem like a decent choice, but I can't find one that uses external power (USB or from the plug) and I would want one with a transmit range of around 50 meters. Thanks!"
If ITMS ever does close, you will not be able to keep your music unless the practice of allowing DRM to be converted to non-DRM (without further loss) becomes generally accepted (i.e. Hell has frozen and or RIAA is out of business)