There's really not too much you can do, aside from call him out on lying. You're not going to be able to convince him to quit smoking - people with addictions need to make the determination for themselves as to when the right time is.
Keeping both of those things in mind, my advice is to let him know that it's not cool to lie to you, and to also let him know that you would like him to quit smoking, but you acknowledge the fact that it is entirely up to him as to when that will happen. Beyond that, I have another piece of advice. Don't give him a hard time about smoking. Don't roll your eyes when he goes out for a cigarette or tell him that he's killing himself. Smokers know that what they're doing is bad, so piling some disgust on doesn't do any good. In fact, it drives smokers to smoke even more.
He knows how you feel about his smoking, and soon he will know how you feel about his lying. Once he knows both of those things, hopefully he'll find a way to quit on his own, and soon. If not, and if it bothers you too much, consider finding a non-smoking boyfriend.
Ladies, what are your thoughts?