To change your phone settings:
Tap the Menu key
Tap Settings
In the Wireless & networks section, tap More...
Tap Mobile Networks
Tap Access Point Names
Tap the Menu key
Tap New APN (Access Point Name)
Fill the Edit access point section
you need your APN to reflect the following settings:
Connection Name: Internet
APN - Access Point Name: Airtel Web
Login - Username: (leave as it is)
Password: (leave as it is)
MMS proxy: (leave as it is)
MMS port: (leave as it is)
MCC: (leave as it is)
MNC: (leave as it is)
hope this will help you