It might have taken longer than the month or two we were promised back in August, but the FetchTV iOS app to use your phone as a remote control has finally hit the market. As for the Android version? That's promised in calendar Q1 2012.
You can use the FetchTV app as a remote wherever you are, so as well as changing channels from the couch, you can schedule recordings while you're away from home or initiate download purchases. The big advantage of using your phone over a conventional remote is that the typing capability is, in all probability, going to be better.
The app is a free download and works on all iOS devices, including iPads.
FetchTV [iTunes App Store]