Well, I'm in your boat. 3-4 cups a day everyday. 5:30 am, 10:30 am, 2:30 pm, 4 pm. Its like clockwork - I need my fix 4 times a day.
Why do you want to quit? There's nothing wrong with coffee, it has magnesium and potassium, which are good for you. I don't beleive caffeine has any serious long term effects (haven't done any research on this though). Coffee makes me alert and focused - I don't think I want to live without it.
Also, if you drink booze often (like I do), supposedly there is research out there that coffee can counter liver damage.