3500 calories == 1lb
Burn 3500 more calories than you take in and you'll loose 1lb. Weight loss is simple math. However, its not easy.
You could loose weight eating snickers bars. I would not rule out any food. You simply have to controll the portion which inturn affects your caloric intake. Untill you get down to 10% body fat, its all about the number of calories.
You will be hungry. What is the difference between a little hungry and a lot hungry, not much as its still annoying as f*ck. If you really want to loose weight, commit to it. A steady loss of 2-3lbs per week is a realistic goal for some time.
Write down EVERYTHING you eat! Keep a journal and be honest with yourself. Count every calorie and weigh your portions. Go to the bookstore and get one of the green pocket food books with all the nutritional info in it.
You probably won't loose significant muscle mass for some time. However, you will loose fat on top of the muscle which will have an affect on your physical perception of self. You'll have to look in the mirror and decide what physical appearance your happy with. I've never seen someone put on muscle without gaining fat or loosing fat without loosing (some) muscle.
Eating a high-protien diet will help preserve muscle. If you're doing 2000 calories per-day and 100 grams of protien, you'll be eating a lot of lean meats, chicken, and vegetables.
Muscle is 73% water anyways. If you feel bad just have some bread and water, you'll carb up quick.
My friend and training partner did the same thing in the past 10 months. He went from 265 to 188 and stepped on stage at the Mike Francois, finishing in the top half of his class.