Greetings from a fellow Alabamian Adam! Great to have you. Do you currently have a bike? If so, that is where you should start. Take it to a local shop, have it checked out and start riding. As John said, the biggest battle will be getting your diet under control. Stay away from the TV. Those commericals are murder! Get a check up and ask you doctor for weight loss advice. Choose your diet and STICK TO IT! We have all tried and failed to achieve our ideal weight. Understand that you are going to have setbacks. The important thing is to keep at it. Join Miss Bumble's Biggest Loser Thread. We weigh in every Monday. A great time BTW as it helps us avoid weekend bingeing. Set weekly goals and share your results with us. See if you can find a local support group. Once you find that you are going to stick with biking, then start thinking about getting a new bike. Trust me, if you fall in love with cycling you will always be drawn to shiny expensive new bikes. Set a goal that you will buy that bike when you reach a particular milestone. My current rides are a 2004 Specialized Hardrock Pro and a 1988 Bianchi Axis Cross Bike. My origional Panaracer Fire DH 2.3 and Marzucci shocks are stored in my work room. I recently wore our my 1.6 slicks and replaced them with a set of 1.75 Panaracer Pasela Tour Guards. I would love to have a Specialized Roubaix, but that will have to wait until I lose down below 250.
The folks on the Clyde and Athena board are extremely helpful and supportive. Visit often. Read, post , discuss, and learn. Once you are cleared by your doctor, start out easy on the bike. You may only need to ride 1 mile per day for the first week. Try adding 1/10th of a mile per day for the next 3 weeks. Drink lots of water, drop fried food, beer, and empty carbs. Don't allow yourself to get too hungry. That's when you really fall off the wagon. Keep low cal healthy snacks around (raw carrots, raw almonds, sugar free Jello and pudding). Force yourself to eat slowly. Make your last meal your smallest and don't skip breakfast.
Good luck and remember; we are here for you. Stick around and enjoy the ride!