speedoswimmer, you are right to assume that this muscle has less to do with your body fat levels and more to do with how well you target it with exercise because it does. I've seen fat guys with it so no, Bruce Lee and Genuine don't hold exclusive rights to Apollo's Belt. The all time best exercise I can recommend are standing twist: you stad feet shoulder width apart and hold a light plate, about five or ten pounds and twist until you are almost looking over your shoulder...move your head if you want, i don't because it makes me dizzy, i'd recommend you don't move it, but moving it might help you at first to get the movement down. You need to do a lot of these for em to be affective. Me, I put my favotite cd on and do these until the end.They can have dramatic affects in a short period.
The secind best are seated leg raises and leg bends...in where you lay on a bench with your hands under your butt and raise you legs either straight or bend them when you bring them up about half way or a little more. It boins baby.
Shit, gotta go to the shooting gallery...may write more later...you look good as you are I think, laters.