The Cornell lectures, which were made available by Bill Gates using Silverlight, are the basis for Feynman's book "The Character of Physical Law". They are referred to as the Messenger Lectures, and are intended for a general audience -- basically anyone at college level (or college level in 1964). I think that they should be required reading by everyone.
These lectures are currently available in various formats on YouTube, as wells the site sponsored by Bill Gates.
These are *not* the Feynman Lectures in Physics, which were based on the freshman Physics class Feynman taught at Cal Tech in 1962-64. This is the famous three volume work, which has usually been published in red covers.
It is the Cal Tech lectures that are available free on-line. There is also an iPad app that has multimedia for some of the lectures -- the 6 Easy Pieces part.
The Feynman Lectures in Physics was the result of CalTech's reform of the teaching of Physics. The books are taken from audio tapes (and photos) of Feynman teaching the two year course from 1962-1964. Other than the parts extracted as the "Six Easy Pieces", they are intended for physics majors (and engineers, mathematicians, etc.). Although some parts are dated, the main reason for reading these books after 50+ years is the quality of Feynman's explanations. They are models of clarity.