Battle Of The Bulge

There is no way to target weight loss to a specific area of the body because your body decides where it wants to put on weight and where it wants to take it off. The midsection is a common problem area for many people.
The best way to lose fat is through cardio exercise. It is important to do a variety of abdominal exercises (including crunches) to keep your core strong, but until that excess fat is gone, you will not see the muscle definition.