I have never smoked, but have quit other addictions (soda, food, etc) and it's HARD. Quitting something has to be something you want to do.
For soda, I quit cold turkey. I craved it, felt sick, was moody, for a few weeks. Eventually I just didn't want it. Now if I take a sip I feel sick and it tastest so gross.
Food is a different story. We need food to survive. I can't quit it cold turkey. I make the things that are healthier my best and only options. However, if there is a cake or something around, I'll take enough for one or two bites and move on. Just to satisfy the craving and get a taste. That won't work with smoking though.
A friend of mine (from here) just quit smoking in the last couple of months. She used Chantirx I believe.