For those of us who are trying to lose weight, I've been using this website to track my calorie intake.
Based on your hieght, current weight, and weightloss goals, you get a daily calorie goal. Everytime you eat or drink something, log it and it subtracts the number of calories in that item from your total so you can see where you stand.
If you eat out or grab something at the grocery store, just start typing it in and it will pull it from it's data base. Click "I ate that" and it subtracts the number of calories in that item from your total. Or you can enter calories manually. It also tracks excercise.
There's a section where you can add your weight in (I do so every Monday, but you could do it every day if you wanted) and it tracks it using a neat little graph. There are excercises and reciepes there as well. I haven't used that part yet, but it's there.
Best part? It's all FREE!! Just sign up and fill in your profile. Try it out. I give it 5out of 5 stars.