Here's another exercise to get a sexy stomach.
1. Lie down on your back, lift your legs, cross them and bend your knees. Then place your hands behind your head as illustrated below.

2. Now slowly raise yourself up.
Attention: Do not pull on your neck, use your abdominal muscles to raise your body as shown below.

3. To complete the motion, slowly move back to the initial position.
Go here for more flat stomach exercises.
Go here to learn more about fat belly.

