Since version 3.0 you don't have to manually add permissions to AndroidManifest.xml. On page http://docs.phonegap.com/en/3.3.0/cordova_connection_connection.md.html#Connection you can read:
As of version 3.0, Cordova implements device-level APIs as plugins. Use the CLI's plugin command, described in The Command-Line Interface, to add or remove this feature for a project:
$ cordova plugin add org.apache.cordova.network-information
If you don't use the phonegap build service you can use cordova instead of phonegap (which is built on top of cordova).
Hope this helps.