it's great that you want to work on this, and you'll find a lot of support around here! couple of comments...
1) diets never work. find relatively healthy foods you dig, and stick to those. find creative yet easy recipies (i think there's a thread on the board for this) but the biggest thing to watch is *portion control*. also, if you have a food that you absolutely must have, eat it, just limit how much. if you try to avoid all the "bad-for-me" stuff, you're bound to fall to a craving, so allow yourself a little bit, to satisfy the craving. also, if you can't get away from sodas yet, at least switch to diet. not the best choice, but will drastically cut calories!
2) exercise doesn't have to be "gym stuff", nor dvd's for tv. yardwork, walks with an intermitten jog/sprint (like up to the store & back), hell, even housework if you go about it the right way (constantly moving, vaccuuming, bending to clean things, etc) can count.
3) it's said that it takes a minimum of three weeks to break an old habit/develop a new one. set yourself a timeframe for 1 month, and commit to only that (at first). by the time you make that 1 month, you'll likely be into the "workout/diet" habit, and it will be a lot easier to maintain.
good luck!