[QUOTE=bfloyd... but what works the lower abs (my main problem) . . . ?[/QUOTE]
There are a bunch of different crunches for various parts of your abs. You can lift your knees to your chest; you can roll your legs to one side or the other while keeping your shoulders flat on the floor, then crunch away on your obliques; leg lifts; point your legs straight up into the air and push straight up with your toes from your gut...I suppose they all have names, but I know none of them.
But yeah, to echo every one else: a reasonable calorie deficit is the best long term solution to (achieve/loose) a six pack.