See, SMS are sent through the carrier.
Either you need to contact carrier for sms packs or you can use few online services which allows sending smses.
Sending sms from Webservice is not a big deal. You need to spend for sms packs only.
Few services are also there which supports sms as email.
Just send a regular email to the following address:
Virgin Mobile: email@example.com
You can also use
which provides SMS gateways