I used to work map databases and programming in a Geography Department and once looked for things like this, but there was never time to delve into this part :
here are a few other things one could snuffle around in :
The obvious Google Maps stuff :
Mapbox (it looks like this has gone open source - good on them)
As the URL says :
Google provides a GeoFencing API there is a tutorial here :
there is a stackoverflow query here :
some sort of library here from above link :
tutorial also from stackoverflow link :
If you really want to push the envelope google CartoType android API ( not free SDK / API evaluation versions )