They have to want to quit. Many of the methods are familiar. There's the nicotine-replacement devices, including patches, gum, nasal sprays, or inhalers. There's a prescription antidepressant called Zyban, which is FDA-approved for aiding smoking cessation. There is also behavioral modification, which can be done in individual therapy or in a group, and then there are the less conventional treatments, such as acupuncture or hypnosis.
People have a lot more options.
At the moment, we've had to be satisfied with incremental progresses. Those two medicines really give us the best success rates, so far, for smoking cessation. A patch containing both nicotine and mecamylamine is now being tested on people. A nicotine beverage that would act something like a patch is also in the works, but it's not as far along as the mecamylamine research. The changes are coming about not only in science, but in the way society sees the struggle against smoking.