Here is one great trick for Airtel free GPRS Just follow the simple steps below:-
I have tested it.Its working in all over US.
For this trick you have to change some settings values in your default internet settings.
Set the APN-airtelgprs.com
Set the Homepage-22.214.171.124
Set the PROXY-126.96.36.199
Set PORT -80
Thats it done enjoy..!!