P2P for cell phones -ZDNet :

FoneShare, an application introduced by NewBay Software, does let people share their collections of ring tones, graphics, songs etc with strangers. FoneShare will debut next year as a subscription service, running over privately owned and operated cellular networks, and the sharing will be done via Web sites controlled by a wireless operator.

Because the networks are private, wireless operators can easily identify which files are being shared and even shut down handsets that are doing a suspicious amount of file trading. "If there's any piracy going on, anywhere, the wireless operator can track you down," Holahan, Chief Executive, said. "It's like the Internet, without all the crazy stuff."