i will have the following set up:

people will be sending text messages to a server, and that server will be forwarding the messages to other phone numbers

i am not sure what kind of framework i should use. 

1. should i develop an SMS gateway and use AT commands?
2. should i just try to somehow use AIM or GCHAT to capture and send SMS messages?
3. would there be a different more suitable configuration?

are there already developed frameworks that are free which i can use? for example i know that i can send an SMS to almost anyone through gchat or aim by sending a message to "+" and the number of the person. is this scalable and can i use it for my own benefit?

any sms developers out there?