Before we once again get our Kevin Rose-colored glasses on and hope beyond hope this is a sign the 4th generation iPhone will support video calling and/or video iChat, we're going to hunker down and go with O2 making a bit of a mess-up on their new iPhone plan web page (above).
Also, it's important to remember that the carriers have no idea what Apple will release for the 4th generation iPhone anyway. Even if they had to test it for video conferencing, Apple would make them wait until they showed it off at a WWDC keynote or something similar because they wouldn't want the carrier to leak the feature. Anyway, with our luck O2 will just be bringing an app see the video but not send any back... Sigh.