Toning the abdominal area has less to do with ab exercises and more with cardio. You must first burn the fat that is on top of the abdominal area. Diet and cardio are really the only ways to do it. The best ab workout I've ever tried was the one from p90x. Download it and for the first week or so don't try to do as many reps as they do in the video. You won't be able to walk upright for days if you do. But it works! I had awesome results in the first week.
As the previous comment says it is not about the ab exercises more about burning the fat on top of your ab muscles, The best way to do this is amend your diet to remove any fat and also do long slow cardio or short bursts of high intensity cardio
Flatten your stomach and slim down your thighs with a few targeted exercises. Add a healthy diet that enables you to lose weight overall and you'll love the way your stomach and thighs look in no time. Do exercises that target both your abdominal muscles and your thighs at the same time to make more efficient use of your time.
cardiac exercises are good for your thighs/stomach and swimming is good too. From experience, I think swimming is the most effective sport I have tried. However, I was recommended Cardiac exercises as the most effective way by many people.