If you want to know what the world's leading thinkers are saying, you'll want to check out the University Channel. Organized by Princeton, but accessing materials from other major academic institutions across the world, the University Channel puts online important speeches made by prominent figures, often coming from the world of public and international affairs. In recent weeks, just to give a few examples, the Channel has featured Noam Chomsky talking about the current crisis in Middle East, Christine Todd Whitman offering her views on politics and the environment, Peter Singer discussing the ethics of food, and Vaclav Havel and Bill Clinton talking together about the challenges facing new democracies. Conveniently, all talks are available in audio and video formats, both on iTunes (audio - video) and as feeds (audio - video). The University Channel offers a great way to pack your iPod with talks that deal with the pressing issues of our time.
For more university lectures and courses, see Open Culture's University Podcast collection.
Also see Open Culture's other collection: University Online Courses & Online Media