I really wouldn't bother with a placebo. Think about it, a sweety, a stick of celery are not cigarettes. They don't work - all they do is make you think about smoking more - you will always associate the placebo with smoking, and always miss smoking because of that.
You will always have the desire to smoke some times. I stopped after 13 years (i'm only 26 now
) one day. And stop telling people you are quitting smoking, or trying to give up.
At this point you are not a smoker any more. You do not smoke cigarettes. It is something you used to do. The sooner you accept that, the easier it becomes.
The cravings work like this: at the beginning you will want a cigarette every thirty seconds or so. The craving will last two minutes. Over the course of 48 hours this will drop to zero need for nicotine by your body. This does not mean you will not want to smoke. You will, its inevitable. You need to just accept the fact that its painful and nasty but it won't last forever.
Will you be beaten by something? Or are you stronger than it?
I think what most people don't think about is not the fact you are stopping smoking (the easy bit of this) but the fact you are actually giving up a series of habits (which are typically harder to break). Think about it - there is not just 'one' cigarette the smoker has. He/she has the first one of the morning, the one with his/her coffee, the one waiting for the bus, the one before the cinema, the one after food, the one after sex (which i miss the most!).
It is not easy; it is a very very hard undertaking. Don't bother trying to do it at the same time as someone else, as you will fall foul to their weakness. You will think "oh it's ok if they have one, i can too" and its destroying. You don't want to be a serial quitter - that's just sooo painful!
Just beat it. You know you can.