If you haven't noticed (or even if you have) the iPhone mockup on the Apple site has only 11 feature icons.
In this case, evidence of absence is no absence of evidence. It would be so unlike design-obsessed Apple to leave all that space there.
Now Gizmodo thinks that 12th space could be held in reserve for YouTube. Not out of the question: YouTube is making nice with the H.264 codec that Apple uses. And of course, Google and Apple are certainly not adverse to working with each other. Both share a common foe- Microsoft.
But I have a hunch that 12th icon could be something else entirely.
Most of the existing iPhone items refer to either functionalities or content-related feature sets on the device. Movies would fit with that.
The fact that The Wall Street Journal reports this morning that Apple is in talks with at least one major movie studio (Viacom) about offering movies for rental and online viewing via iTunes could mean that capability might be added to the iPhone to receive these movies via transfer from a user's iTunes, and then store these movies on the device for the duration of the rental period.
Obviously there would be storage size issues but with the play life of the movie being only a few days, there might be a way to either shrink the file size after expiration, or let users delete expired movies from the iPhone anyway.
My hunch that Movies is the 12th iPhone icon is also prompted by the timing of Apple's negotiations with the studios. If the 12th button were for a feature or amenity already signed, sealed and delivered, well, it would probably already be shown. But the fact that Apple is participating in what seems to be the final stages key content acquisition on a parallel time track with the release of the iPhone (June 29) really makes me think that something could be up.
Something that could well result in the iPhone's 12th icon being Movies.