getting abs is mainly your diet more so than what exercise you're doing. A good portion of your results comes from your diet anyway. Everyone has ab muscles but most have layers of fat hiding them.
stay away from sugar and beer
eat almonds, yogurt, oatmeal, and eggs (hard boiled)
and remember that everyone has their own uniquely shaped abs so don't count on getting abs like those fools out of the magazines.
best way to work your abs is to involve them in everything you do. In and outside of the gym. When you do pushups, you should tighten your abs hard, likewise when you do squats, deadlifts, curls, etc. When you're sitting down, you should take that opportunity to tighten your abs. Use your rectus and transverse ab muscles.
and swimming works better for abs than any cardio. Stationary bike, elliptical or even jogging have next to zero ab contraction--that's mainly hip flexors.