I have yet to play with (or indeed spend much time reading about) iOS4 so it is possible that I am totally wrong with this one and this missing feature is actually supplied by the latest iPhone operating system. But if not … what about plugin input methods ?
That is allow other people to write extensions to the on-screen iPhone keyboard. Whilst Apple have undoubtedly come up with the best possible method for inputing text on a touch-screen, there are always a few who would like to try other ways such as :-
You could even allow users to craft their own on screen keyboards to allow easy access to extra symbols such as emoticons – which for some strange reason are available on certain far eastern keyboards but not on English ones ?!?