My favorite is the tomato "leather" I learned from Rosalind Creasy.  Prepare tomatoes as given for making tomato sauce, then cook down the crushed tomatoes to a paste consistency.  I use a small dehydrator in my humid climate:  spread the "paste" onto screens purchased with the dehydrator or onto something like teflon sheets that will fit your model and dry at about 125 degrees until leathery.  Tomato leather can be rolled up and stored in the freezer, where it occupies much less space than frozen tomatoes, for use as a flavor enhancer as is or reconstituted by replacing the water that was removed for a recipe's required tomato sauce or paste.

When I have too many tomatos and not enough time to preserve them right away, I stick them in the freezer! I wash them but leave them whole, unpeeled and with the cores in. Takes five minutes. Then in winter when the urge to make the tomato sauce/curry/chili is upon me I take a couple out and while they are still frozen rinse them in hot water for about 20 seconds. The skins slide right off. Chop them up or leave them whole and use them where ever you would use canned tomatoes (without making your kitchen well over 100 degrees in the summer!)