Get EyeTV from Elgato for about $150. Their iPhone app will almost certainly be adapted for the iPad. There is no monthly charge and you can watch all the major networks (ABC, CBS, NBC, FOX, PBS) in HD both live and recorded. It depends on being in a large city in most cases (to have all the networks on local stations) and a decent roof mounted TV. The best characteristic is that you have no monthly bill.
2/19/10 at 12:20pm