You have made a huge step in wanting to make a change...
Wattage (our resident mod) has great tips for keeping yourself motivated as well as keeping track of what you eat.
Keep in mind, you HAVE to exercise as well as eat right, even if that exercise is throwing on the iPod and walking at a sufficient rate of speed to get your heartrate up for 30 minutes a day.
It's a slow process, and you'll hit plateaus, but you can do it!!