DO NOT TRY THIS TUTORIAL IF YOU DON'T HAVE SHSH SAVED! It ruined all my settings and I had to restore!
The Cellular Data Network option will give you the opportunity to change the settings for connecting to the Internet on your iPhone. This tutorial works for iOS 3.x, but for iOS 4 Apple changed the settings a little so it's time for a new tutorial.
Step 1
Connect to your phone via SSH or with ifunbox.
Step 2
Navigate to var/mobile/library/preferences/ and copy the com.apple.carrier.plist file to your computer.
Step 3
Open the file with a program for editing .plist files (I use a program called "Property List Editor") and pass the following lines of code immediately above the line of code "CarrierName", so that it looks like the image below:
APNEditabilityTypemask 1 AllowEDGEEditing
After this change, the option should appear in General>Settings>Network. If it does not appear then reset the phone.
A simpler installation method would be by accessing this site from the phone, copying the respective codes and editing the file with iFile.
