If your waffle iron or pan has a nonstick surface, you should not use cooking spray. Cooking spray builds up on nonstick surfaces and eventually becomes tacky–rendering the non-stick coating useless. Brush oil lightly over the surface of your pan instead: if the spray build-up hasn't ruined the pan, this should work.
Also, be sure you are not trying to take the waffle out of the pan too soon; if it is not thoroughly cooked, it will stick.
For some fabulous waffles recipes, see Making Waffles Just Got More Delicious.
Recipe: Oatmeal-Honey Waffles