One of my favorite apps on my iphone is MY Fitness Pal. I also use it on my computer so updating is quick and easy. My Fitness Pal.com keeps track of measurements, weight, calories and exercise. It's so easy to use and they have every food imaginable online with all the nutrient values.
When I did weight watchers one of the keys to success is tracking and I have to say I was not good at it. Writing things done is painful and time consuming, I'm a more online kind of girl, plus my phone is pretty much an appendage.
The thing I like about it, is it keeps you conscious of if you are having your daily allowance of sugars, fiber etc....I was shocked, first thing I have is coffee and I love the flavored coffeemate. I would use all my sugar for the day on 2 Tbs of creamer......so my goal is to somehow enjoy soy or milk again.....gonna be harder than given up wine!!