When FaceTime was first announced quite a few people were bummed that it required WiFi. A few weeks later a tweak at a small price was added to cydia that enabled you to FaceTime over 3G. 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.
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.
Directly below <dict> in capabilities as shown below.