We know FaceTime was required WiFi very useful, but wifi is not with you all the time, but 3G networks can be with you all the time. So 3G networks maybe more useful than wifi, but Apple did not make facetime support 3G work, When iOS5 was released some of the internal builds had FaceTime over 3G enabled by default. It turns out that the final version of iOS 5 also includes FaceTime over 3G it’s just turned off. Thanks to hamzasood, I was able to turn it on! Head over the break to see what you need to do.
Here is a short guide by funkyspacemonkey to help you make FaceTime over 3G enabled by default
1. You will need a jailbroken iOS 5 device with FaceTime and 3G. Since the 4S and iPad 2 aren’t Jailbroken yet that leaves the iPhone 4.
2. Use your favorite file browser such as iFile for iPhone or iExplorer for mac and windows to navigate to /System/Library/CoreServices/SpringBoard.app/
3. Inside you will find a file called N90AP.plist open it.
5. That’s it enjoy