Webcasts and Podcasts are presentations of different types and are made sharable over the Internet. Many universities and educational institutions have made the public lectures and courses into webcasts or podcasts and have made them available to everyone for free. These can be lectures on various topics such as science, politics, history, art, poetry, or almost anything else. The speakers can be famous scholars or politicians, authors discussing their books, or they can be entire university courses.

AUR has cataloged some of the most important ones, and they are all available here. Unfortunately, we do not have the time to catalog each webcast, only those by institution. The closest there is to a searchable database of these materials is University Channel, though Princeton University. This does not include all of the webcasts in the AUR catalog, however.

Also, look at ITunes U, which includes lots of podcasts and webcasts, many of them available for free.