Lynn from The Hungry Little Caterpillar has a terrific post that puts into words what I've been trying to say about motivation.
Seriously, don't wait for motivation. It's over-rated. If you wait for motivation to give you the kick in the pants you need, chances are you'll still be fat when this time next year rolls around. Just go and DO IT! Eat healthy. Exercise. Of course you won't feel like doing it. So what? You have a goal, so start working on it!