This is a small application to demonstrate a class I have written to send SMS text messages via your PC modem. The class will connect to a TAP centre (I'm using UK vodaphone) and send your text message. The only cost you incur when sending your message is the cost of the call to the TAP centre.
The TAP centre will let you send only around two messages at a time, so you will have to disconnect and reconnect for more messages to be sent.
There are two examples in my code that you can view.