I quit smoking 2 1/2 years ago on my first try. (I had been smoking for about 8 or 9 years.) When I decided to quit I asked my doctor what would help and prescribed wellbutrin (an antidepressant) for me. It helped SOOOO much. Don't ask me how it helps, I have no idea.
Another thing that helped me is changing my behavior patterns. For example, I liked to smoke after I ate, so when I would eat instead of sitting down and chilling out, I would immediately do busy work until the craving passed.
I still have a craving for a cigarette every now and then especially when I'm stressed or p*ssed off or drinking. But then I remember how nasty they make me smell and how bad my breath stinks when I smoke and that changes my mind. (What a nasty aftertaste!)
*Edit*-- Here's another wierd thing that helped me. I keep a pack of cigarettes in the freezer. I don't want them as long as I know that I can have them whenever I want. As long as I know that they're there I'm cool but if they weren't I would probably crave one like crazy. It's bizzare I know, but you gotta do whatever works. Of course that pack has been in the freezer for over 2 years and probably would make me barf if I tried to smoke it.
*Edit 2*-- I smoked a pack and a half a day of Marlboro lights for 8 years.