GPRS Quadband Module for Arduino offers GPRS connection to your Arduino board. It includes the HiLo SAGEM communication module. You can send your data by SMS or do missed calls from your Arduino to mobile devices… or to another Arduino connected to this module. It is necessary an antenna in order to establish a communication.
Documentation:
Tutorial: basic guide for getting started with the module.
Schematic
AT Commands
SAGEM Module Info
Download the Fritzing library to include in your electronic designs here