There are many variations available for iPhone and Smart Phones alike aimed to help people quit smoking. One that we found well-featured is iQuit for iPhone. It allows you to pick a goal time frame, then sets up a timer that gradually gets longer in between how often you can have another cigarette. Hopefully with a place to view your goal process and possibly the help of other cessation products, this app can really be useful in helping smokers quit. (Also helps with curving alcohol and other addictive substances).
Download the iPhone app iQuit from the iTunes store.