iPhone as AirTunes receiver Is there an app that will receive AirTunes? I want to use iOS4's new AirPlay capability to send audio from one iOS device to another. I realize I can use Rogue Amoeba's Airfoil and Speakers to stream from my Mac to said iPhone, but I want to send from my iPhone to another iPhone.

What I'm trying to do is avoid buying an Airport Express device by just hooking up an old iPhone and running an app...
If you are willing to jailbreak your iPhone there is an app on Cydia that will turn your iPhone/iPod/iPad into an AirPlay speaker. It has its issues, but it works fairly well.

If you have want to mess with it there is an article here:

http://www.macstories.net/tutorials/how-to-turn-your-iphone-and-ipad-into-airplay-speakers/