So Yet another SMS question :-)

I researched, but could not find a solution to my requirements.

I do not have a GSM modem, nor can I pay for any Third-Party software for sending SMS. Also I spent quiet some time learning SMS gateways. But when I experimented with it, it failed.eg: I emailed number@textin.in but no message was received at the receiver's side!

The application I am building takes up phone-numbers from a database and sends a different SMS to each number depending on certain condition. 

Being a student, I just have to look for Free websites like 
 <http://site3.way2sms.com/content/index.html> and others,but don't know how to use them programatically!

So my straightforward question is : "How can I send SMS using just the internet?".  

My SMS recipients will all be resident in India. And language is C# using Visual Studio 2010.

Please Help......