DisplayCast is a free and open-source screen sharing application designed for scenarios in which the wired/wireless networks and computation resources are abundant.
DisplayCast comes with three components:
The Streamer, which is the source component and allows you to share the entire screen or a portion
The Player, which is the real time receiver that allows the created windows to be dragger around using the GUI.
The Archiver, which enables you to capture a stream into a H.264 movie
Detailed instructions on how to install and use the DisplayCast utility on your Mac are available HERE.
DisplayCast is cross-platform and it works on Mac OS X and Windows. Binaries for the Windows platform are available on the project's homepage.