One of the iPhone 4's standout features is FaceTime, the free video chatting software developed for the iPhone that lets two people see one another while they talk. Unfortunately, Apple and AT&T have restricted FaceTime in a really big way: It only works via Wi-Fi and won't work via 3G. Unless you hack your iPhone.
Comex's JailBreakMe browser-based jailbreaking tool was released over the weekend. Once successfully jailbroken, iPhone users will be able to install third-party applications not approved by Apple. One of them is called My3G. It costs $4 to download. That program enables FaceTime to work over both Wi-Fi and 3G networks.
According to the developer, Intelliborn, "My3G makes Apps believe that they are on Wi-Fi instead of 3G. With My3G, you can now watch Hi-Def YouTube videos, use Skype/Fring/Other VoIP apps over the 3G network," and of course FaceTime.
The biggest reason Apple, AT&T and other network operators have restricted FaceTime to only Wi-Fi has to do with the bandwidth required to run the application across the wireless networks. None of them has admitted how much data the application uses, but they've hinted that they are still working things out behind closed doors.
The enterprising folks over at 9to5Mac tested exactly how much data is used for FaceTime chats over 3G. They concluded that FaceTime video calls run approximately 3MB per minute of air time. That's not terrible. It's not great, either.
A 10 minute call will cost you 30MB (roughly). If you subscribe to AT&T's 200MB plan, it's not deadly, but you will chew up your entire 200MB allotment in a little over an hour of FaceTime use. That really puts things into perspective.
If you're going to unlock your iPhone 4 and install (and use) My3G for FaceTime calls via 3G, I'd highly recommend you're subscribed to the 2GB plan. That gives you a lot more flexibility.