I have this problem to. The worst thing for me is that DH help each other in this addiction. One of us will drive to the shops and by tim tams or block of chocy (or both).
I've taken up knitting as I find this helps take my mind off food, gives me something to do.
But don't give up chocolate completely. Allow yourself to have a piece when you really, really want it. Sometimes by completely cutting something out can make you want it more.
Like JoMarie, brushing your teeth after dinner helps, even chewing on some gum.

Don't kick yourself if you fall down, just pick yourself back up and try again.