I stumbled upon a nice service where you can easily send out text messages using an Arduino. It’s tropo.com. You can use a developer account and texts are free, or a production account where they are only 1 cent. Attached is a test sketch I made sends texts with an Arduino and Ethernet shield. You basically send a HTTP GET to tropo with a token, your cell phone number and the SMS text message.
Tropo_SMS.ino (3.54 KB)