I'm sure not everybody know but you can download free college lectures on utunes in iTunes. Classes from Harvard or berkley or even MIT. The video is filmed during their classes, a really great resource.
I watch the MIT physics videos and some of the chemistry ones, from some other website. They're all great Edit: this is the link I use http://www.learnerstv.com/Free-Physics-video-lecture-courses.htm They have a ton of videos on just about every subject
Yale also has some great ones along with Tufts (gots to love Daniel Dennett) here are the links Online Video Lectures and Course Materials — Open Yale Courses Index - Tufts OpenCourseWare
I use the YouTube versions. I tried using my iphone but video eats the battery too much and it's easier to see on a larger screen. I know MIT and CalTech have video's there along with many other colleges. Specifically I know MIT has a program to put their courses on the internets for free, sometimes you get the one's that tell you the link to their classwork so you can do the homework also. (although there's no grader of course) p.s. the stickied link at the top of this section has a ton of good links also if anyone is looking.