Here's a great place t start:
http://www.freshpreserving.com/
Whatever you do when canning...FOLLOW THE DIRECTIONS! Other than that, it's not too difficult. I can a lot of tomatoes, sauce, and salsa, but also freeze a lot of tomatoes whole. I just core them and put them in freezer bags...they peel easily when thawed and go great in stews and soups in the winter...very simple.