HopNet Software has an interesting Windows Phone app on the Marketplace design to help those looking to lose a little around the middle. PlusPoints is designed to track your diet by a point system, the same point system used by Weight Watchers in their PointsPlus Program. To complete the Weight Watchers tie in, if you use the Weight Watchers eTools, you can access Weight Watchers' mobile site (Weight Watchers account required) from within the app.
For those not enrolled in Weight Watchers, you can still take advantage of the PlusPoints app by tracking your dietary points. Points are based on the fat, carbs, fiber and protein content of food. There is a calculator within the app that can be used to determine a food's points. Daily recommended points are calculated from your sex (male or female), age, height, and weight. From there you simply keep track of your daily intake, trying to eat within the daily point allowance.
PlusPoints is a free application (ad supported) and you can download it here (opens Zune) at the Marketplace. If your dieting and need a way to track your calories, PlusPoints might be worth checking out.