In your Android Mobile Phone Select
Settings -> Wireless & networks form the Main Menu
Then Select Mobile Networks -> Access Point Name
Now add a New APN -> Click on the Settings and enter your details there.
APN Details are different for each service providers.You can get the APN details by searching in Our website or get it From the List of International GPRS Setting for Telecom Service Provider across the Globe.
Android Mobile Phone APN Settings Step By Step Procedure: