Crunches are good for the ab muscles. But only in combination with a good, clean diet.... and time.... will the flab there go. There is not such thing as spot reducing. The bodyfat stored there was probably the first place and will be the last place to go. Diet and exercise will up your metabolism to burn the fat, where ever it is stored, as energy. But it is from all over, as a rule, and not just in one place.

Have patience, you are getting there.