Thanks to the wonders of technology, it’s now possible to access lectures by prominent Geographers from around the world without ever attending their classes (or paying the expensive fees to get into their universities). David Harvey is the standout example here. You can view his seminars on Karl Marx’s Capital here and watch a clever animation of another of his lectures here.
Richard Walker is another. His Berkeley lectures on the Economic Geography of the Industrial World are accessible from the Berkeley podcast web site here (as are many other lectures in other disciplines).
Both Harvey and Walker are heavily influenced by Marxism. There might be some non-Marxist Geographers podcasting. If you find some, post some links.
ps. Do you know that you can listen to lots of the Eye on the World posts by clicking on the Odiogo link at the top right of the page?