Lots of people buy GSM/GPRS modules to add the ability to send and receive text messages from there micro-controller projects. Why not use a old Android phone or tablet. The premium version of NMEA Bluetooth Access adds the ability to send and receive text messages, send emails through the users Gmail account, and post tweets to Twitter. Arduino, Raspberry Pi, or any other device you can add Bluetooth capabilities too will benefit.
Continually tested and works with;
Freeboard - Open source Navigation System
OpenCPN - A open source chartplotter and GPS navigation system