You cannot send SMS by yourself using just Internet. You will need an
SMS gateweay. Please see:
http://en.wikipedia.org/wiki/SMS_gateway[
^].
Providing such gateways is a commercial business, so you have to find the provider yourself and pay the fees. However, I've heard something of some businesses providing it free of charge on certain conditions, cannot tell you more about it. Please do your search, if you want to go if for this.
—SA