1. A computer network-based distributed presentation system for displaying one or more video streams output by multiple video cameras located at multiple presentation sites, comprising: a general purpose computing device located at each of the presentation sites; a display screen located at each presentation site which is capable of simultaneously displaying one or more video streams in display sectors of the screen and which is controlled by said computing device; at least one video camera located at one or more of the presentation sites, each of which outputs a video stream comprising views of the presentation site where the camera is located to the computer network; a computer program comprising a display director program module executable by the computing device located at each presentation site, wherein the computing device is directed by the display director module to, determine on an on-going basis which of the video streams output to the computer network are to be downloaded for display on the screen at the presentation site where the display director is running and select what sector of the screen the downloaded video stream or streams are to be displayed; controlling the display screen so as to display the downloaded video stream or streams in the selected sectors.