lol...well, I wouldnt say "setting up a script"
It really depends on what your trying to achieve and whether you are "paying" for the service to deliver your text messages.
The best way to achieve this is to get SMPP access to a Message Center. Once this is connected, you will have the ability to send messages on the GSM network.
Charges for the messages range from 3p - 6p per message.
I would expect the service you are looking to "piggy back" on is actually using illegal entries into mobile networks. If this is the case, there is never any guarentee of the message ever being delivered.
If you want a true SMS gateway and system,. drop me a pm. But expect it to cost you $
What's my reasoning and justification for these statements? I used to have the above connections and was sending in excess of 6,000,000 messages a month in its prime
Rgds
MAtt