'SMS send' and 'SMS via e mail' module set up

Hi, I have installed the modules 'SMS send' and 'SMS via e mail'. But i dont know how to set it up. please help. From where can I get the following?

E-mail gateway domain: *

Gateway number usage mode: *

In india the mobile providers are Reliance,Airtel,Vodafone,Tata Indicom, and Idea.

Is their service paid? or free?
Thanks