Cellular mobile devices and Google Maps can be used to provide fast and accurate localization without GPS. Using a database of cell coordinates, the location of an object can be precisely determined.
Position location with GSM cellular – [Link]
Tronixstuff has released Part 2 (for part 1 click here) of their tutorial series on using a GSM cellular modem with the Arduino. In this part they cover how to use the telephone network to control an Arduino board via a SM5100B Cellular Shield. [via]
Tutorial: Arduino and GSM Cellular – Part2 - [Link]