People love putting their Arduinos in interesting and remote places. while it may be possible, it may not be practical to run out and collect data from the devices. That is where this GSM / GPRS shield comes in handy.
Based around the SIMCom SIM900 that puts this device on the lower end of the price scale, (49 Euro for the module, ~60 Euro for the module mounted on a breakout board, or around 85 greenbacks) makes this module an interesting target for anyone wanting to add cell phone connectivity to a project.
To take this a step further [Boris] whipped up a nice shield PCB for the Arduino and Arduino like footprint users to make connections between the 900′s breakout board and the Arduino layout a snap. Electrically its just wires, and a LM317.