Move Action monitors your webcam and can take some action when movement is detected. The action could be to lock your PC (requiring a password to reactive it), save a JPG image to disk or run an external application. It checks the webcam at particular intervals and compares the current image with the previous one. If there is a significant change detected between images the program will take the configured action(s).
The license of this software is Freeware, you can free download and free use this video surveillance software.