when i feel like having a snack, i have the habit of wanting something crunchy and sweet, so i find my favorite yougurt/low fat and i add grape nuts cereal to it. This combination cures my sweet tooth, and the grapenuts give me that constant crunch that potato chips give me.
When you get a real sweet tooth and you are about to cave in, go and brush your teeth. After you brush your teeth your mind will forget about the sweets and your mouth will not want to get dirty with junk food. If you snack you will choose something cleaner than chocolate or soda. Trust me!