To help you get started on the right path, here is a list of my 5 favorite core (abdominal) strengthening exercies that will target all aspects of your core:
* Bicycle Crunch - With your hands behind your head and your knees bent at 90 degrees, straighten one leg while bringing the opposite elbow to the knee still bent at 90 degrees. Continue this pattern alternating sides for 30-60 seconds.
* V-Ups - Lay flat on your back with your arms extended over your head, bring both arms and legs up at the same time to meet at the half way point. Lower and repeat.
* Kick-Ups - Lay on your back with your hands behind your head and your knees bent at 90 degrees. Extend your legs up as you lift your upper back off the floor.
Stability Ball Crunches With Rotation - Take a stability ball or a bosu ball and place the sole of your lower back at a 45 degree angle on top of the ball. Keeping your hips down by rotating your pelvis back (sticking your butt out) and bring your upper body off the ball while rotating an elbow to its opposing knee. Lower and repeat.
Iron Horse - On all 4's straighten the left arms over your head and your right leg backwards. Bring the left elbow to the right knee and repeat. Once you complete 20 repetitions follow the same steps on the other side.