Lecturefox appears to be a site devoted to gathering all the free lectures from various prominent universities (MIT, Caltech, Harvard, and Carnegie Mellon, just to name a few).
This site is pretty cool, considering it saves one the trouble of looking for all these things themselves. There is a blog, but the home page is [...]

Podcasting is wonderful… not only can you listen to your favorite geeks, but you can also listen to academic lectures from top universities.

List of Academic Lecture Podcasts
via Digg