Motorola iDEN handsets on the NEXTEL system have the ability to output a NEMA data stream via the data cable to your computer for a moving map. There also is a java app available for a monthly charge (requires network coverage and GPS visibility) to give you turn by turn audio and visual (arrows) directions between useer selectable points. The test mode on the handsets allows a lat/long and velocity readout, in a pinch you can get a lot out of that if you had to, and that test mode (I think) works off-network, out of coverage