Does anyone know how I would go about scripting one of these? Any point in the right direction would be amazing. Going to use it for when people visit my website, they put there phone number in (cell) and get sent a SMS verification code and they confirm the number in the text box to continue.
If you want to send SMS messages to people, you will need to use an SMS Gateway. I have recently added SMS functionality to my site. I signed up with a company called TxtLocal as they have a great API that can convert between SMS and Email.
You can create a PHP script that sends the message to the SMS Gateway by email. They convert it to a text and send it to the user. The user replies by text message, the SMS Gateway converts it to an email and sends it back to your script.
Very easy to set up and quite cheap too. As I say, I signed up with TxtLocal as I live in the UK. You may want to search for another gateway. Just look for the SMS to Email service.
If they are entering the code that you send them into a box in your online application (as I would expect) then you don't need to pay for a gateway service. You just need to have them enter their cell number and choose from a list of cell phone service providers that you will define. You will need to define the table of cell phone providers in your application along with the corresponding email address format that you need to use for each one. If you do a search, you can probably find a text version of a list of providers if not some php code. The other option is to go to the website for each cell phone provider and get it there. I have done this and it isn't a long or difficult task.