On the Cats Who Code site today there's a new tutorial showing how to send SMS messages from your PHP application with the help of the TextMagic service.

Over the years, Short message service (SMS) has become a very important way of communication, and many businesses are looking for easy ways to send automated text messages to their customers. In this tutorial, I'm going to show you how you can send SMS using PHP and a third party service called TextMagic. Its very easy to do!

They step you through the process - creating a TextMagic account, configuring the account with your own password and creating a simple script that includes their own API library and sends the SMS request.