M@S:Mozilla for beginners:Videos
In the Mozilla Developer Center(MDC) there is page (Video Presentations and also on Google Videos) that has the videos they are producing that can help you learn how the Mozilla codebase works and how to take advantage of its technology in your own applications and extensions.
NOTE: Check all the content in here.
Some of these videos have been recorded in Seneca on the Fall 2006 semester, check the Guest Lectures.
NOTE: You can download the .mov files from here.
NOTE2: The video files follow this license, CC-BY-SA
These are the videos we suggest you to go over: