I have, to date since March 1, 2009, lost over 100 pounds. The picture in my avatar was the end of May, about 40 lbs down from my starting weight of nearly 300 lbs.
You've probably heard it before, and for me, it's true. You can't diet and be successful, you have to make a lifestyle change.
I went to www.caloriecount.about.com and used the tools there, along with the forums, they even have a nutritionist that you can ask questions of...all for free. The tools available are awesome, the two I used the most were the burn meter and the calorie counter. By entering your height, weight, age, and activity level they will tell you how much you burn in a day, how many calories you should have to lose about a pound and a half per week, (1% of your current body weight is a safe amount)
The best advice I got while I was using the board? "Don't do ANYTHING to lose weight that you're not going to be happy doing for the rest of your life".
Let me know if I can do anything to help you!! Good luck, and toss that cabbage soup out! ;)