If you are new to iTunes, read this primer. Or go straight and browse the 100,000 lectures, presentations, videos, readings, and podcasts it offers. Everything is broken into 13 categories, from Business to Teaching & Education. There are ESL podcasts, recordings of bird sounds, a series on Darwin’s relationship with God, videos on human body parts, and recordings of and interviews with Lead Belly, Pete Seeger, and Woodie Gutherie, above.
On the right of iTunes U are the 20 most popular downloads. Enjoy!