Agree with PPs. Brush your teeth, don't bring it into the house in the first place (I have NO will power if its in the house!) and it also helps me to write down what I eat. I don't write down the # of calories or carbs, just WHAT I eat. Looking at "1 bowl of ice cream" is tough when I'm struggling to lose weight. Especially next to "potato chips".

Go to bed.

Are you snacking because you are hungry or do you just want something to do? I was watching (I think Dr. Oz) and he talked about the apple test. When you want to eat something...go get an apple. If you could eat the apple and feel satisfied, then you are truly hungry. If you look at the apple and don't want to eat it, then you are not hungry. If I am truly hungry, I grab a hard boiled egg or two. The protein satisfies me. If I am not hungry, I will grab some water or tea and read or watch tv.

I agree with PP's that the key to preventing snacking is to have fewer snacks on hand. Just don't bring it into the house. I can't eat crap cereal - although I would love to - because I am NOT going to the store at 9pm.
Also, figure out what kind of snack you go for, and have a healthy alternative - ie I love love love ice cream and I have a tendency to mindlessly eat while watching TV. A pint of B&J, in my mind, seems to be ONE serving. Oops. I freeze small bowls of grapes instead. They are cold and sweet, and take some time to eat. Also, if I eat a bunch I don't feel too badly about it. Chocolate covered strawberries or choc covered frozen bananas are good too.
If all else fails (I am assuming you are female, sorry), paint your nails. Difficult to eat for a while.

I've been trying to cut out night carbs for years.