ChatFX adds a miscellany of video effects to iChat.
I actually pitched a similar concept to a video-oriented software producer about two years ago but nothing came of it. The specific possibility I see for software such as this is not so much the predictable, silly uses of it. I see the possibility of adding an additional layer of composed meaning to the videoconference interaction. I visualize participants adapting cinematic techniques to the image – zooms, jumpcuts, wide-screen ratios, moody slow pans and the like.