My sister told me I should get this app for my iPhone, so I did. It's free and awesome. It calculates how many calories you should eat daily, based on your height, weight, and goals. It tracks your progress as you go.
You can search for just about any food and tell it how many servings (down to the 1/8 fraction if you want), and it keeps track of calories. (Or you can quick add if you know the number of calories.)
I don't know if they have it for Android, but I assume so. You can also use their website:
I've been wanting to join WW online, but haven't been able to justify spending the money, so this is a great free substitute. Yayyy.