How can I send a text message/SMS with PHP? [duplicate]

Possible Duplicate:

any good php tutorial on how to send sms to phones?

I'm trying to figure out how I can send text messages/SMS messages with PHP to phones. Is there a w开发者_运维技巧ay to do this without having to pay for some service? Also can I make a way for people to respond to texts/SMS? For instance when they receive the message can they respond and that data be stored in a MySQL table or something?

You can send an email in the format of the user's carrier, using formats listed here.

If you'd like to receive messages back and process them with business rules, you'd need to pay for an SMS gateway. Not sure where you are located, but I've asked a similar question on finding a decent Canadian provider here.