VNCRobot is a tool based on a VNC client. It can control remote computers running a VNC server via the RFB protocol. VNCRobot provides its own proprietary scripting language and a set of useful features which enable you to program, verify and reproduce behavior of the remote computer and provide a comprehensive report, which makes it a powerful tool for automated testing of any software. For real usage examples see the How To Use VNCRobot document. There's also a VNCRobot 1.2 demo which demonstrates basic functionality on an example of a simple automated test case.
VNC is a remote control software which allows you to view and interact with one computer (the 'server') using a simple program (the 'viewer') on another computer anywhere on the Internet. In simple words you can see the server's desktop (also called 'frame buffer') in your viewer and you can operate the server as if you were working on a local machine. The viewer actually sends all your mouse pointer moves, clicks and drags and keys typed on your keyboard to the server which sends back updates of the remote desktop. For more information on RFB protocol and VNC technology read the documentation on Tight VNC and Real VNC sites.
VNCRobot is an extension of VNC viewer. Apart from standard viewer functions it provides a scripting language which can simulate any user action and send the appropriate messages to the server.These features allow you to write a script consisting of such commands and execute it repeatedly to reproduce a task.