I have been using my fitness pal app for the last four years. It's a free app that allows you to log in your goals, keep a food diary and log in your activities. It tells you how many calories you are consuming and burning.
I love this app. It syncs with Runkeeper and my Garmin Vivofit. It has a really cool barcode scanner and you can upload recipes through the website.
If you have a smartphone and you are serious about cleaning up your diet, I would highly recommend it. (This is my own opinion. I am not working for or being paid by myfitnesspal.com)