A couple of years back, MIT (Massachusetts Institute of Technology) released a press note revealing their intention to make available free of cost the study notes which includes lectures, tutorials, video and audio of lectures of all their courses online. This was big news then and was welcomed by aspiring professionals and institutions the world over. And MIT Opencourseware was the platform chosen to deliver on their promise.
In fact you can find a huge collection of video lectures (which this post is about) on the MIT opencourseware website. The lectures are divided into their respective sections which makes it quite easy to find what you need.
Also check out this web page which features links to over 177 video lectures from the Berkeley University as well as links to other online educational resources. A very good resource worth bookmarking.