I'm using John Walker's Eat Watch concept as described in his online book, The Hacker's Diet plus meal planning from Bob Arnott's Revolutionary Weight Control Program.
Not sure how revolutionary it is but the main ideas are "feeding forward", eating "hard" foods in the morning and building muscle to give your body more mass with which to burn more calories during the day.
Feeding forward is simply eating before you need it and hard foods are things like whole oatmeal, dense pumpernickel bread or beans that are difficult for your body to process.
The two most useful pieces of that are: first thing when you get up in the morning have a glass of skim milk to kill your hunger, and a few hours after lunch (around 4pm for me) have some high-fiber food (I eat Fantastic Food's Black Bean Soup) so you don't get tempted to pig-out for dinner.
The misc.fitness.weights FAQ has lots of good information about weight lifting.
Compute your resting (basal) metabolic rate;
i.e. the number of calories your body naturally burns each day.
Compute your Body Mass Index (BMI) or at the same site, figure out your ideal weight.
I use a few palm-based tools to keep track of everything
John Walker's Eat Watch (PRC file) (documentation) includes an exponentially smoothed weighted moving trend average chart to compute your real weight extrapolated from your daily scale weigh-ins (which, as you might have noticed, fluctuate all over the place).
This really helps to keep you from getting discouraged when all of a sudden you're up 5 pounds in one day or have a plateau of the same weight for days in a row.
The moving average line gives you a truer picture of what's going on.
Eric Sink's Fitness Record (PRC file) (documentation) keeps track of what you eat.
He also documented the principles behind the software as well as its changelog.
My moving average