Airtel offers both manual and automatic settings. Automatic settings are usually used for mobile devices like phones and tablets. However, if automatic configuration fails manual settings should be employed. To configure your mobile device automatically, text Internet followed by the make and model of your phone to 232. For example, to configure Nokia 5230 SMS Internet Nokia 5230 to 232 You will receive the settings over the air. Save it to your mobile device.
Here is Airtel Manual Settings
Airtel Manual GPRS settings for WAP
Port: 8080 (not always required)
Access Point Name (APN): internet.ng.Airtel.com
Authentication: Normal (Not always required)