MultiScreener is a set of free applications that synchronize the playback of Quicktime movies on multiple computers, using a local network to tie them all together.
There is a Server and a Client. The server plays a movie and also sends position information over the network. Each client “listens” to the server and subtly adapts its movie playback speed to stay in sync. There is no limit to the number of clients.
Looping and de-interlacing are available, and all settings are automatically saved for unattended startup. MultiScreener can output to the computer screen or external video devices (like DV cameras or decks). There is no native resolution or frame-rate, so all Quicktime video formats are supported.