Here is everything you need to know to SAFELY can tomatoes:
National Center for Home Food Preservation | How Do I? Can Tomatoes
I can lots and lots of tomatoes--this year, I have 44 tomato plants.
I make a roasted sauce that works well for pasta or pizza--I cut the tomatoes in half, and arrange them in a single layer on a greased half sheet pan. I roast for 1 hour at 400 degrees, or until the tomatoes are shriveled and some are a little browned. This removes the water, just like simmering on the stovetop, but you don't have to stir or worry about scorching.
I also add sliced green peppers, onions, celery and garlic cloves (whole). I scrape all the cooked veggies into a bowl when they are done, and use my immersion blender to 'smoothify' them--I don't bother to peel the tomatoes. We all need more fiber in our diets!
Roasting the veggies brings out the sweetness, so I add vinegar to brighten the flavor--amount varies depending on the kind of tomatoes, but generally a cup per gallon of the finished product is a good starting point. I don't usually add salt or herbs/spices--I wait til I am cooking to do that.
Because I am adding low acid veggies to the tomatoes, I pressure can this mix, using the times for green pepper canning. I can in pint or half pint jars, because I live alone.
You can waterbath tomatoes, but you do need to add extra acid to be safe. I pressure can almost everything, because it is quicker and doesn't heat the kitchen up as much, because you are not heating a huge canner full of water.
I freeze some tomatoes, too--just throw whole tomatoes into a ziplock. When you get ready to use them, pull out what you need, thaw slightly, and the skins will slip right off. Chop and add to your recipe.