Take a quick visit to JailbreakMe, let Comex benevolently exploit a huge security hole in iOS’ native PDF rendering, then install the $4 My3G program through Cydia and you can have FaceTime running flawlessly on your iPhone 4 even without a WiFi connection. But how much is that FaceTime call going to drain from your monthly data allowance?
9to5Mac has done the tests, and it’s actually not as bad as you might fear: in fact, the average FaceTime call only uses about three megabytes of data per minute.
They conducted their test using “lots of movement” so that the FaceTime compression algorithm was kept on its toes, and a five minute FaceTime call ended up slurping up 14.7MB of data. That’s pretty modest usage against a 2GB cap. Clearly, the prohibition against 3G FaceTime isn’t in consideration of iPhone 4 users’ wallets, then… but AT&T’s own congested 3G network.