I use a pedometer and then record my steps at
Walker Tracker.
Wearing a pedometer doesn't make me more aware of what I'm eating, but, as Cheryl said, it's a very good way to keep an eye on how active I'm being.
Also, using Walker Tracker is fun because it keeps a graph of your steps walked, along with total miles, etc., and you can actually see the progress you're making as you go along.