Diet is ALWAYS key.
Fuyu, from what I've noticed, I think the leanness will come over a longer period of time, but I've always read that there isn't much SIGNIFICANT truth. Either way, it doesn't hurt because at least you are exercising. I've noticed a distnct change in my endurance since I decreased weight and increased reps, which is EXCELLENT in my opinion.
Regarding your fat loss/muscle gains, it really depends on where you are physically. If I had a lot of fat on me, I'd want to drop a significant amount of that before I even thought of weight training because I'n not a lineman in football... I now prdominantly engage in board sports, which is what you want to do, and this means lean is where you want to be... flexibility, agility and athleticism. Stretching is also important.
Once again, diet is key... replace peanut butter with almond butter, white bread with whole wheat, even the kind with extra fiber... eat fish, chicken a lot and veggies. I eat a lot of fruits, but usually earlier in the day so I can burn the sugars throughout the day.
Basically, if I were you, I'd do a lot of cardio and minimal weight training if I wanted to lose 30 lbs. Work on your core as well... strength here is very important in general, but especially for board sports.
SbSpaz, if you want to lose gut, CARDIO!!!!