Hope you don't mind a blatant plug :-

TMJ-Mobile software available free from www.trackmyjourney.co.uk connects your mobile phone to a bluetooth GPS device to show your location on a map and can also create a GPX log file of your track. The Map Organiser tool allows OpenStreetMap maps to be downloaded for viewing on the phone offline.

Work with most recent Sony Ericsson, Nokia and BlackBerry phones.

Cheers!