GpsDrive
GpsDrive is a car (bike, ship, plane) navigation system. GpsDrive displays your position provided from your NMEA capable GPS receiver on a zoomable map, the map file is autoselected depending of the position and prefered scale. Speech output is supported if the "festival" software is running. The maps are autoselected for best resolution depending of your position and can be downloaded from Internet. All Garmin GPS reveiver with a serial output should be usable, also other GPS receiver which supports NMEA protocol. GpsDrive is written in C with use of the GTK+ graphic toolkit and runs with Linux and FreeBSD.
For 770, the most natural way of getting connected to gps device would be using "BluetoothGPS"
It would also be nice to be able to use it without GPS, just to download some maps.