How can I successfully try to cut out sodapop from my life?

I am addicted to soda pop. I won't lie. I get headaches if I don't drink the stuff. I like milk and water too, but mostly soda pop. Unfortunately, I'm gaining stupid belly weight now and my teeth are not in the best of shape. I want to cut soda pop out of my diet completely. Now, I drink roughly 2-3 soda pops in a day and milk at all my meals. Can you help me devise a plan to cut out soda pop from my dietary habits?