Does anyone know how to create an sms interface?

[adim]

You know how on facebook/twitter you can change things on your online profile by sending an sms to a given number. How does that work. Where can I get software that can give me that functionality?

[David D]

You can't send SMS messages directly, you need to make a deal with someone (for example: http://www.intellisoftware.co.uk/ ) who can get them onto the phone system.

How you send and receive messages with the entity depends on what interfaces they provide. In the above example, you send messages by POSTing to an URL (just like submitting a form) and get messages back by email or POSTed to a URL on your own site.