TeaShark, a mobile browser like Opera Mini, allow you to access Airtel GPRS for FREE. Shockingly it has nothing to do with modifying any Airtel settings or any kind of hack. I tested it personally throughout the week but I haven’t been charged a single penny.
Here is how I used this…

* Download TeaShark v. 312. Its free and being JAR file it can be installed on most handsets.
* Open it from your mobile and select AirTel Live as access point.
* That’s it! Open any site from TeaShark and you won’t be charged anything.

Note for the first time, when TeaShark starts, it may take more than one minute to initialize. Also this one time initialization may fail many times.
Here are some famous sites’ mobile version...

* Gmail: m.gmail.com
* Orkut: m.orkut.com
* Facebook: m.facebook.com
* Twitter: m.twitter.com

The whole thing seems a fortunate coincidence for mobile users and unfortunate one for network operators. This trick cannot be termed illegal as you are not cracking any software or modifying any configuration. For the same reason, I think this will take longer to get rectified.
Please keep in mind that AirTel may charge you all of a sudden in future of this free ride. So please use it at your own risk! ;-)