We can manage our BMI information by using this app.

Emerio scale for iPod touch, iPhone and iPad
Bluetooth enabled Smart iOS Enhanced Weight Scale.

The Emerio scale is a weight tracking solution completely integrated via Bluetooth to your iPod touch, iPhone and iPad.

Product Description for Emerio scale app

For many staying in shape and getting healthy, at the same time keeping track of progress can be a bit of a challenge. With the Bluetooth Scale and the accompanying App, it becomes convenient for you to keep track, stay informed and monitor your health.