Yale apparently provides a service called Open Yale, which currently has seven full courses available in MP3, Flash and QuickTime format online. There's one class each in Astronomy, English, Philosophy, Physics, Political Science, Psychology and Religious Studies available.
The other day I listened to the first two lectures from the Religious Studies offering: Introduction to the Hebrew Bible. Very interesting, though clearly done from a Religious Studies not Christian of Jewish theology point of view.
Most of the classes look interesting to one extent or another. If you feel like dusting off our academics via iPod, check it out.