Thanks to Jacques Ravel for pointing this out. U. C. Berkeley has begun posting many of its science classes as Podcasts which are avilable for download at a special Apple Itunes Site. Also posted are some lectures such as one by George Smoot who just won one of those Nobel Prize thingies. It seems Stanford is doing a similar thing although it does not seem as extensive.
Note sure what other Universities are doing this (I know some classes are podcasting but not clear how many Universities are doing it as extensively as Berkeley).
If anyone else knows of other such efforts please let me know (also see this list of free academic podcasts).