You will need to focus on diet and exercise. Start by keeping a food log of your current dietary habits. That means Protein, carbs, fat and calories of EVERYTHING you put in your mouth for a week. Total the Protein,carbs,fat and calories at the end of each day. After seven days total your daily amounts to reach a weekly total and divide by seven. This will give your average daily calorie intake. This is your starting point. Come back and post the results and we can help you clean up your diet and post some specific calorie/macronutrient recommendations. Your food log is your most valuable weapon in the war against body fat.
In the meantime, you need to join a gym and learn how to exercise properly. You may want a personal trainer to get you started if you are unfamiliar with proper lifting techniques. Just make sure they focus on free weights. Don't listen to any line of bull about machines being safer, they have their place in your routine but the foundation should always be free weights. There are a lot of bad/lazy personal trainers out there so be careful. Once you've got the technique down and done some research you can strike out on your own.
There are numerous sites with information, one of my favorites is
http://www.testosterone.net, they have an archive of all their previous issues and it contains a lot of good advice on diet and training routines. This board will also be a great source of information and support. A lot of us have been doing this for a very long time and we want to see you succeed, you'll find people here are infinitely helpful. I would also recommend picking up Arnold's Encyclopedia of Modern Bodybuilding. It will be a good introduction to the bodybuilding lifestyle. It has pictures of exercises and is very motivational IMO.
As far as motivation, take a polaroid of yourself in a pair of shorts and put it on your refrigerator. You will see it every morning and it will strengthen your resolve. Once you start making progress you can tape more pictures showing your transformation. If you stick with the iron it will help you battle depression and it's an amazing stress reliever, it can be the most therapeutic experiences in the world to have a great workout. Don't give up and you will transform your body. Remember, the best revenge is living well.
