I like the Excel-based tools provided (for free) from John Walker's
Hacker's Diet. The nice thing about it (for me) is his focus on your
weight trend rather than your
current weight which basicly means that minor variations in your daily weight get averaged out... and you get a much better picture of how you're really doing.
(As long as your trend is moving downward, you're losing weight)
I thought his book was pretty good (written in a tongue-in-cheek manner) though I felt he spends a little too much time trying to convince you that losing weight is a good idea.
Anyway, you can use his spreadsheets without ever trying his diet. They make pretty graphs for you, print nicely, and generally help keep track of your weight.