The Wi-Fi-enabled music player technology will appear at the Consumer Electronics Show: I received an in-person demo months ago of MusicGremlin's very interesting technology which keeps a music catalog resident in portable devices that license the technology. Any users near to other MusicGremlin subscribers can exchange music files freely because the files use digital rights management (DRM) to secure playback. Thus users who choose to enable sharing can let other people view their collections. The system can use ad hoc Wi-Fi networking or wireless LANs. It could also work with 3G cellular networks; it's ecumenical.
I've been waiting for the company to announce a hardware partner, as they didn't plan to manufacture their own devices. Apparently, they were tired of waiting themselves and will release their own hardware in the first quarter of 2006.
The company has licensed music via MusicNet, 2,000,000 songs in full. They'll have a variety of options, including a monthly unlimited music subscription, a la carte pricing, per-song downloads, Web-based listening, and preset music channels.