I have been working out for about 6 months. I am trying to gain muscle mass. So I have been eating 5-6 meals per day. I drink 2 protein shakes a day. I lift weights and can tell I am getting stronger but I can also tell I am gaining weight in my stomach. I am going to start "cutting" so I can define the muscles I have built up. What kind of diet should I follow in order to lose more weight in my stomach.

Stick to a low-fat, high protein diet with lots of fruits, vegetables and water.

You need a calorie deficit. Go to FitDay - Free Weight Loss and Diet Journal and open a free account, and work out how much you are really eating. If you are gaining belly fat, it's a good bet you are eating more than you need, also probably too many refined carbs.

What sort of weight training are you doing? Concentrate on big compound lifts like squat, deadlift, bench press, pull-ups, stiffleg deadlifts, bent over rows, military press, stuff like that.