Weight training will help burn calories and increase your metabolism to burn fat. It will take fat from all over your body, not just the muscles worked. And that's one good reason for concentrating on large muscle groups, like legs, back, and chest, rather than spending a lot of time on smaller muscle groups, like arms and shoulders, because you will use more calories for your workout.
A good combo for reducing abdominal fat is squats (to burn a higher amount of calories), cardio, and clean eating. Ab exercises will tone the muscle, but they don't burn enough calories to affect fat stores noticeably.