I also recommend doing a taper for a about a week (or shorter) using Yerba Mate if headaches are a problem. Yerba Mate is an herb...NOT TEA. It has a moderate amount of caffeine, is very high in antioxidants, and has no artificial or extraneous substances that are hazardous to your health. In addition, the caffeine "buzz" your get is extremely mild, meaning kinder to your adrenal glands as they try to recover.
I specifically recommend Guayaki (brand) Chai Spice Mate, Mate Chocolatte, or the Pure Endurance Mate (This is the best caffeine cessation IMO.) The each have about 20mg of caffeine per cup, making them perfect for addressing withdrawal headaches. Be careful...there are brands that mix tea with the mate and regular mate is much higher in caffeine (about 60mg per cup).
I've struggled with giving up almost every vice in the book since becoming a convert. These are the things my research yielded and what I personally have used to quit caffeine successfully.
I hope the info on the last 3 posts will help someone.