I am working on it, and I promised to write more about it under the Projects section here when I got a chance, but since you asked...
What I have is a combination CDPD/GPS unit that talks to the empeg through the serial port. The unit has inputs for two antennas, one cellular and the other GPS. With a subscription to a CDPD service provider, the empeg gets wireless IP connectivity via PPP with the unit. (CDPD is 19.2Kbps cellular digital packet data.) GPS data is also transmitted over the PPP link in UDP packets, so an application on the empeg can receive and process them using ordinary sockets.
Actually the local reception of GPS packets is not working correctly atm due to some addressing issues that I am working out with the vendor. So currently I can retrieve GPS data from elsewhere on the net (where is my car?) but not from the empeg itself (where am I?). Hopefully this will be fixed soon.
The other problem I'm having concerns running anything at the same time as the empeg's player software. Since the player locks down most of its memory there is very little room to run anything else (like pppd) regardless of available swap space. I'm hopeful that this will be addressed by the empeg folks -- or maybe the Mark II is the solution; I don't know yet.
Finally I would like to have some way of taking control of the display to interact with the user. I've worked out some ideas involving fetching map data from GPS coordinates over the net (via CDPD) but I don't yet have a good feel for how well the empeg could display a map on its 128x32 2bpp display; I'm hopeful. There are always other possibilities such as giving directions via voice synthesis, or transmitting the map to another device (such as a Palm unit) via IrDA.
That's everything in a nutshell. I'm happy to talk more about it and share ideas; send me
email.
-v