I have been eating great and working out almost everyday, but im not losing weight, what can i do?

I do yoga in the morning and i do kickboxing at night. i weigh 225 and i want to weigh 155-160. i thought for sure i could accomplish this by october 2010, but i am not losing weight! at all!! i eat breakfast lunch and dinner, always healthy. i eat a snack in between lunch and dinner, usually fruit or vegetables. i havent drank any pop at all since i started and have been drinking plenty of water.