Hi Sean,
You did not mention you numbers. How much overweight are you?
Man boobs can be caused either by hormonal imbalance, having high estrogen and low testosterone levels. This is a medical case that only can be dealt with by visiting your doctor. However, it might be caused by excess fat in the chest area, which is probably your case since you mentioned that you have a weight problem.
The obvious way to get rid of your moobs is through exercise, specifically weight training. This type of training will increase your muscle mass, which is very important in losing fat. Muscles need a lot of calories to sustain themselves. Thus will make you lose fat all day long.
Concentrate on exercises that involve big numbers of muscles at the same time, such as squats and dead lifts. Of course you should not forget exercises that hit your chest area directly, such as push ups and bench presses.
