A new class has just started, and the material has been updated for iPhone OS 3.0. Videos of the lectures are available for free in iTunesU one week after the actual class.
Watching the videos (of the 2009 class) and working on the assignments has been the best iPhone programming exercise I’ve done so far. Highly recommended.
Follow the class here: http://www.stanford.edu/class/cs193p/cgi-bin/drupal/