Like a few commercial television networks before it, PBS has launched an iPad app designed to stream the network's content to your iPad on demand. PBS for iPad is available for free right now on the App Store, and has full streams of lots of classic shows. There's some new content as well -- Circus is a show that's been created just for the iPad app itself. But there's also some Masterpiece Theater and Julia Child in there, as well as other well-known standbys of the government run and donation-supported broadcasting network.
The app also has schedule information about what's on TV, as well as a DVR-style feature