Congratulations.
I was just talking to one of my ride buddies this morning about smoking [I was at a dinner party last night and I really felt the effects of second-hand smoke this morning]. The thing about cycling is that it is FUNDAMENTALLY incompatible with smoking. You can't do both, so you have to chose between the cigarette and the bike. All things considered, I think you'll find yourself chosing the bike. Smoking a a short-term thrill, cycling is something that is fun to do and which improves your life immeasurably by doing it.
My advice -- which you didn't ask for, but which I'll give you anyway -- is to USE the bike to wean yourself from the cancer sticks. Whenever you feel a craving that you can't handle, just take the bike out for a quick ride. It doesn't have to be much -- just five or ten minutes -- but you'll find that the ride ITSELF will minimize your cravings.
ALSO, make a point of cycling right after you've cheated and fallen off the butt wagon. When you can FEEL what cigarettes do to you, you'll stay away.
If the choice is between smoking and cycling, then it's not really much of a choice, is it?