"I'm assuming you want a PDA. or something cool like that. If the overhead isn't too bad, use a webservices call. Can't really do it with Flash on the Pocket PC, since remoting is horribly slow. But if you wrote some sort of .NET app it wouldn't be too hard. "

Mapping user's locatin using GPS and ColdFusion :
ArcIMS and ColdFusion Users: Ploting Client Side GPS Coords