Mark Twain said something along the lines of, "Who said quitting smoking is difficult? I've done it a hundred times." I'm too lazy to find the exact quote :P
Avoid situations where you'd typically smoke (bars, morning coffee breaks, etc.), have something to help with the oral fixation (gum, toothpicks, candy, etc.), and don't beat yourself up if you falter a bit and smoke a few.
I'd also suggest keeping a tally of the amount of money you saved each day; being able to look down and see the amount of money you didn't spend on cigarettes can lift your spirits a bit when you're feeling like crap.