The Open Electronics GSM/GPRS/GPS modem includes a header for an FTDI USB serial chip and a GSM module. Plug one into your computer and after a few short commands into a terminal, you’ve got a serial ...

If you are looking for a compact GSM/GPRS module, you can get the SIM800L from most eBay traders. It is not the most judicious choice, but you can build your own basic GSM projects with a cheap modem ...