How do I kick my caffeine habit?

I’ve been addicted to Mountain Dew since I started college. It’s really the only caffeinated beverage I drink, but I’m almost up to a 2 liter bottle a day. I’ve tried cold turkey, weening myself off slowly, switching drinks to something a little healthier or even similar tasting, but in the end I always regress harder than when I started. Does anyone know of any tactics or have any ideas one how I can shake the habit and keep clean?