- SeeedStudio GPRS Shield v1.0 manual
- Shield Schematic
- SIM900 AT Commands (for the module on the shield)
- Arduino and SIM900 GSM Modules (Tutorial by TronixStuff)
- Google Voice (to send and receive SMS Text for free)
- Similar shield
For the service, I chose TrackFoneWireless.com because they offer a no-contract, no-monthly fee, good for 90 day service. It includes 180 minutes talk, 180 texts and 180MB Data. This may or may not end up to be the best option. However, it seems reasonable for $28 including FOUR (SIM cards - only one of them is needed but they supply two sizes for GSM and two more for CDMA).