When last we checked in with the BuddyTV Guide app (in July), the capable recommendations and program search in the app were plenty useful. The main drawback, unfortunately, was that you could not use it to control your TV and set-top box unless you had a Google TV-powered setup or a TiVo Series 3. Other cable or satellite providers' tuners didn't have an API that BuddyTV could use to change channels or set DVR timers.
Good news, then, for subscribers on AT&T's U-verse television services; you can now control your receiver with BuddyTV. Anything you could do with your physical remote should be possible with the virtual remote living in your iPhone, and since there's no IR blaster involved you can theoretically change the channels from anywhere you happen to be (much to the delight, no doubt, of your roommate/spouse/kids/pets).
I'd expect to see more BuddyTV integrations with other IP-enabled TV service providers soon, since you can already control Dish Network and DirecTV receivers with their own apps, and likewise for major cable providers. BuddyTV is free on the App Store.
There's a little video demo below; enjoy.