ifiMob
ifiMob.org introduces an idea prompted by the iPhone. Any iPhone owner who wanted to could be the disk jockey of his own radio channel. He could play music, talk, sing, whatever. Anybody with the ifiMob software could see all the channels within wifi range, and tune in to any one. Channels that enable it would allow listeners to talk, too. You could squelch talkers you don't like, from just your soundscape. The channel list could show its music's pulsing beat, so that you could pick a channel by the rhythm of its dancers.
I hope Apple opens up the iPhone enough to make this idea possible. I hope somebody writes the software. I want to use it.