What are some abdominal muscle flattening exercises?

Abdominal exercise: While sit-ups can increase abdominal muscle mass they will only minimially help you loose stomach fat, if any. To loose adipose tissue work on a cardio mix (walking, running, biking, swimming, circuit training, etc - mix it up). Keep in mind that you can not target one specific area of the body to loose weight, and over time the adipose will decrease in many areas of your body (stomach included).

Lose weight.: For flatter abdomen eat healthy & get physically active. Calories burned > calories consumed. To tighten ab's: crunches, reverse crunches, exercise ball crunches, pelvic thrusts, lying leg raises, side bridge & “bicycling” exercise on back. Engage in regular aerobic exercise (i.e. running, swimming, Nordic track, bicycling, kickboxing, walking, cross country skiing, hiking, etc.)