I have an abundance of fresh tomatoes every year. A really simple way of preserving tomatoes is washing them, take off the stem and throw them whole into a freezer zip lock bag. When you need some for soup (or whatever) you just take out what you need and pop them frozen in the soup. The skin floats to the top or you can zap them first in the microwave for 30 seconds and the skin just fall off. I also put individual servings of soup in containers and put the calorie count on the top, then pop them into the freezer.