tangogps is an easy to use, fast, and lightweight mapping application 
for use with or without GPS.  By default, tangoGPS uses map data from
the Openstreetmap project.  Additionally, a variety of other repositories 
can be easily added.  The maps are downloaded and cached for offline use 
while you drag or zoom the map.  Furthermore, you can conveniently pre-cache 
areas with tangoGPS. 

If connected to a GPS, your current position and track are shown on the map,
and you can log positional data for further processing, e.g. for geocoding 
photos or uploading streets to Openstreetmap.