Weightbot: simple weight tracker for iPhone and iTouch
I snatched up Weightbot right away when I found out it was on sale for a buck during the holidays, and I was not disappointed. Its basic functions are pretty intuitive: move the slider to a date, click on the weight display, and set your weight. Other handy features: switch from pounds to metric, set a target weight, enter your height to get a BMI calculation, set a privacy code, and back up your data to a web account. The coolest feature by far is graph mode, though. It's a quick way to visually track your progress, and it includes your target weight and a trend line.
[via Daring Fireball]