I also quit "cold turkey", never used patches or gum and didn't gain weight. You really have to want to quit for it to work, if you're only half-hearted about it then you will fail. As for the weight gain, that's just a myth, if you don't eat any more than you did as a smoker then you won't gain weight. The reason most people gain weight is that they eat more after giving up the smokes.

Good luck with it, you really can do it!