Conversations with History
Manan Ahmed recommends Simon Schama's presentation on his latest book, Rough Crossings, on Google Video. There's also a brief clip on The Power of Art.
Google Video offers nearly 200 programs in Harry Kreisler's series,"Conversations with History." Kreisler blogs about it at Conversations with History Blog. His Conversations on Google Video include Niall Ferguson on Money and Power; and Ferguson's appearance on a panel discussion:"The Empire Dialogues: The U. S. and the World Order." YouTube also has excerpts from his series, War of the World: Episode One and a subsequent episode on the Wall Street Crash.
You can search Google Video and YouTube for other historians of interest. Arthur Schlesinger, Jr., for instance, looking a bit frail already twenty years ago; and he's still going.