Here's an interesting demo video from Comcast that features an iPad as a remote control with a few extras. In the demo, Comcast's Brian Roberts shows how to use the app to search for programming (both TV and On Demand), change channels and even program the Comcast DVR. Pretty neat.
Once paired with your cable box, simply browse the TV schedule or the On Demand options. To jump to a show, simply tap its name and presto! The cable box changes channels. Likewise, you can tap an On Demand feature to start it playing. The keyboard will make searching a lot easier (think Apple's Remote app with the Apple TV).
What's really neat is the invitation feature. If you'd like to watch a show with an iPad-wielding friend, you can send an invitation to his iPad (as long as he's set up with Comcast and the app, of course). A message appears on his iPad ("Frank has invited you to watch "LOST." ) All he needs to do is tap accept and his TV will switch to that show. Neat.
This is only a demo and there's no information on when it'll be available, but we're eager to try it out. I reminds me of the days when I could change TV stations with my Newton. Sort of.
It's worth noting that both the big US satellite TV providers, Dish Network and DirecTV, already have iPhone apps for DVR control and scheduling. Mike R. reports that he has successfully used the Dish app on his iPad to change channels and program his satellite box, much to the amusement of his family.