I'm one of those people that has been mostly skinny for most of my life. I recently started working out this past March, and I have noticed some moderate gain in muscle mass since I started. However, I've always had this conflict between choosing to get rid of this fat around my stomach or lifting to gain more muscle. It's weird, because I'm mostly thin except for the fat around my stomach (quite possibly a beer gut). Is there anything I can do to burn down the fat a lot while gaining muscle in my upper/lower body at the same time?

its very hard and time consuming to do both at the same time. IMO, its better to concentrate on one at a time.

Im quite muscular around my upper body, which it looks quite impressive at my age of 15. Im actually working on my Abs at the moment, heres some details:

The reason most of us can't see our abs is because they're covered by a layer of fat. What this means is that:
· Doing AB - exercises to achieve a six-pack is an impossible goal
· The only way to see your six-pack is to reduce your body fat
· The best way to reduce your body fat is with cardio, strength training and a healthy, low-calorie diet

This doesn't mean that AB - exercises serve no purpose--strong abs support your spine and protect your back.