You might want to talk to your doctor about a prescription for zyban - it is supposed to reduce nicotine cravings while also suppressing the appetite, so those who are quitting don't gain as much weight. Since it doesn't contain nicotine, you can continue to smoke while taking it and wean yourself off smoking at your own pace. It isn't safe for everyone, but might be worth discussing with your doctor. That way you might not feel so pressured into quitting right away.
Littlered, one thing to remember about sugar-free gums and candys - they may be better for your teeth but most have just as many calories as the full-sugar versions - and sugar-free products sweetened with zylitol, mannitol or sorbitol can cause diarrhea and stomach cramps if you use too much. Think about other things instead - carrot and celery sticks, frozen grapes instead of hard candy, fat-free pretzels. Clean out the fridge and cabinets of the junk food before you quit smoking and stock up on healthy snacks - it's a lot easier to resist temptation when the chocolate cake isn't sitting on the counter. At the times when you would normally smoke, like after meals, try doing something totally different like going for a walk, or put on some music and dance, or go outside and wash the car, anything to keep yourself distracted. Otherwise, if you snack when you would normally smoke, you're just substituting one bad habit for another.
And think about rewarding yourself with something special with the money you save by not smoking! Not to mention how much younger you will look and feel!