Apparently, we use to much data in unlimited plans for mobile phones, so the short of it is, O2 is cutting theirs amongst others. The carriers don’t quite seem to get it, when you say ‘unlimited’, that means UNLIMITED! For the carriers who are so thick they didn’t get that, let’s break the word down. Limited; to have a limit on something. Un; the opposite of the following word that is now part of the word. Therefore, un-limited basically means without limits, so when they offer unlimited data, they should have thought that maybe by offering the user what they want for once, they might actually use the opportunity to use it. So back to the main point, if face time ever goes 3G, it will cost the user a massive amount as a YouTube video costs a lot to watch on your iPhone (it didn’t used to as it was unlimited data usage) think how much a forty minute video call would cost!
UPDATE: FaceTime is only on WiFi, unless you jailbreak your phone.