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!"
I believe it is the 2550 but includes a wireless doggle that is inserted into the USB port. It also has File Sharing on the PC which is good for playing DIVX files located on you PC. It works just fine after a bit of configuring the thing to see the network.