Just open iTunes, go to the iTunes Store and look down the column to the bottom and you'll see iTunes U. Click on this and you'll discover hundreds if of courses, lectures and seminars offered in audio and or video format by no fewer than 45 top colleges and universities and the list is growing daily. All for free. Just be careful not to exceed your download limit but that's between you and your service provider. That happened to me, so now I go to the library or a coffee shop with my laptop and download all I want, for free.
I go to sleep listening to courses. I
Also in iTunes and equally free and no less informative and or entertaining, are thousands and thousands of podcasts, covering more topics than you can even think of, so practise using their power search and before you know it you'll get the hang of it. The same goes for podcasts with regards to teaching young folks.
The last lecture I listened to was called, "
How Unequal Can America Get Before We Snap?"