My newest website obsession, which was actually my wife's first, is thedailyplate.com. Erin and I recently joined a gym and along with that have begun being better about what we eat. The Daily Plate is a cool site which can help you keep track of your eating habits and exercise routine.
Each day you enter what you ate by searching their extensive database of foods, and based on the number of servings it keeps track of your caloric intake and other nutritional facts.
Keeping track of your daily exercise works much in the same way as entering your food. You search the database for everything from running to mowing the lawn and denote how long you participated in each exercise.
Another cool piece of the program is that based on your age, height, and weight it will tell you what your daily caloric intake should be and give you suggestions based on your fitness goals. It will also adjust based on your amount of exercise each day. It's pretty nifty.
If you're looking for an easy way to keep track of what you eat I totally recommend The Daily Plate. It makes eating healthy more fun than it already is.