To get a six packs or stronger abs, you will have to do crunches, sit ups, leg lifts, butt-ups, and also planks. This will enable you to exercise all your body parts and achieve your abs. Get more detailed tips on http://www.bodybuilding.com/fun/vinced11.htm.
Do sitt ups and to work your side, lay on your side with your arms out and lift your legs up sideways as you pull your arm and pull back over your waist. doing normal workouts help better than the expencive stuff I think.