The SIM808 GSM GPRS Module is at the heart of our Adafruit FONA 808 - Mini Cellular GSM + GPS Breakout. For people who want to integrate a cellular (GSM/GPRS) module into their design without the full breakout, this hand-solderable module is pretty nice! Please note we don't provide any tech support for this module, but we do have a schematic as well as a collection of datasheets and app notes that can be used to interface.

• Quad-band 850/900/1800/1900MHz - connect onto any global GSM network with any 2G SIM (in the USA, T-Mobile is suggested)
• Fully-integrated GPS (MT3336 chipset with -165 dBm tracking sensitivity) that can be controlled and query over the same serial port
• Make and receive voice calls using a headset or an external 32Ω speaker + electret microphone
• Send and receive SMS messages
• Send and receive GPRS data (TCP/IP, HTTP, etc.)
• PWM/Buzzer vibrational motor control
• AT command interface with "auto baud" detection

Here's the GPS specifications:

• 22 tracking /66 acquisition channels
• GPS L1 C/A code
• Sensitivity
• Tracking: -165 dBm
• Cold starts : -147 dBm
• Time-To-First-Fix
• Cold starts: 30s (typ.)
• Hot starts: 1s (typ.)
• Warm starts: 28s (typ.)
• Accuracy: approx 2.5 meters

You'll need to add all of the supporting circuitry that is required, such as antennas, power regulation, any level shifting, LEDs, etc! You can check out our SIM808 Eagle placement object in the adafruit Eagle library.