Michelob Ultra is their low-carb beer, and it's OK. Less than 3 carbs a bottle. Also, Lite Beer (from Miller) has a little more than 4, I think.
Of course, Dr. Atkins recommends all things, including alcohol, in moderation. He specifically lists several non-carb hard liquors, but I don't drink spirits very often. I remember one of them was Tequila, which stuck in my mind because the very smell of straight tequila gets the gag reflex going. You see, I had a violently unpleasant episode involving tequila when I was in college... but that's a story for a different day and a different thread.
Of those two Miller Lite is 1000X better. That Ultra carb tastes like carbonated funky water and has about the same kick to it. I prefer Killian's(used to be Corona before the Mexico anti Iraq thingy), but that's another story :)