Here's a nice story about a Colorado woman who lost 30 pounds in three months after having her ninth kid (wow). Her husband also lost 40 pounds (although he started off heavier).

The full story

There are three things in this story that I find interesting:

1. They combined regular Wii Fit with a portion control diet. No matter how good Wii Fit might be, I don't think you can loose more than a few pounds without also changing your diet. When a Mars bar contains 300 calories, it's very easy to undo any good work you might do an the balance board.

2. They did it together. I think that if you can, it's good to do this with other people. The combination of support, and a little competition, can make a real difference to how successful. Wii Fit makes this really easy so long as you share your scores.

3. The psychological effect of measuring yourself regularly. I think that the frequent dose of honest assessment from the Wii Fit is a big factor in getting results. Setting aside arguments about how useful BMI is (especially for kids), I think those numbers hammer home your current situation. If you see it as a challenge, and don't just give up, I think the effect can be very positive.