I have the same problem. I call it the 8 O'clock munchie monster
And I agree with carter about the calorie counting. I'm new to calorie counting and I have to admit it really does help me see where my problem lies. By looking at my food journal I bet that if I stopped my night-time mindless eating that this weight would all fall off because I don't really have problems with my meals or any other times of the day.
Night-time eating is a very bad habit for me because I'm not even hungry. I just want to munch, on anything.
My resolution for 2013 is to kick my munchie monster to the curb. It's tough but I know that if I put my mind to it I can stop with the mindless eating. It almost got me last night but I prevailed!
I wish I had some coping skills to offer you but I don't because I'm just starting out trying to break this bad habit of mine. Hopefully someone will come along with some great advice.