Hi!
I'm not quite 300 pounds, but I feel like 299 cuts it PRETTY close, so I'll give it a shot: you're doing well so far, by my standards!
It's all about diet and exercise. Find out a reasonable goal for you - if you feel like that motivates you, and perhaps even spoil yourself with something non-food related when you reach it. It can be done!
I've been thinking alot about how bad we treats are bodies, and I feel as though 2010 is the perfect year to fix it in! You are worth it, and your body is too. Start by making smaller changes in your diet, and read about different plans and find one you want to follow - even though it's "just" Calorie Counting, at least you've got a plan you're sticking with. That's good for being accountable.
Good luck on your journey! Remember: you can do this!