A Python module which makes it easy to carry out GIS related operations. Look up coordinates of addresses, locations, and landmarks. Has a geocoding function. Can calculate distance between two points on the globe. Pretty straightforward to use.
An openstreetmap app for android which keeps tabs on your GPS coordinates and shares your location in an anonymous fashion with a random Target ID and tracking code. Can share with chosen people or the public at large. Can transmit and receive data via SMS.