Myfitnesspal works. I use it and Runkeeper for estimating calories burned when cycling, walking, or hiking. I also wear a heart rate monitor when I exercise, especially when I am in the gym on an elliptical or treadmill.
In 2011, I lost 84 (280 -> 196) lbs from March 1st to Thanksgiving. My wife, kids, and parents thought I looked too skinny. No one recognized me. I have gained about a third back. I am on the way back down again. I am probably going to shoot for 210 lbs.
You have to be very honest and accurate about what you are eating. I only eat back about half of my exercise calories. When I lost the 84 lbs, I honestly didn't go over on my calorie goal from march to thanksgiving. I logged in and tracked every calorie eaten for that time period. I was motivated.