I quit smoking in October, sorta by accident. I got sick and couldn't smoke without coughing up a lung, so quit for a week while I recovered. (Gotta love that swine flu!) After that, I decided that I'd see how long I could go without smokes, and it's been (with a couple of relapses while drinking) a successful endeavor.
The key, I think, is rewiring your expectations and finding a way to change your behavior. Think about what it is that makes you crave a cigarette, and change that behavior. For example, I crave cigarettes when I sit out on my back porch. It was where my wife (also quitting) and I used to relax in the evenings with a cigarette and a glass of wine. In order to avoid craving cigarettes, we don't sit out back and chat any more. We relax with our glass of wine in a different room in the house.
Good luck! It's a hard road, but worth it.