I've always been interested in saving seeds of vegetables that aren't hybrids. Tomatoes have got to be one of the favorite crops grown in any garden. General instructions on saving tomato seeds include the words "ferment" which is a little scary to me--that's the last step before "rot"!
A friend of mine eased my fears from saving tomato seeds last year. All you do is get a clean paper towel, cut the tomato, and SMEAR the seeds onto the paper towel. If you can space them out a little bit, that works great because when you're ready to germinate the seeds, all you do is "plant" the paper towel and voila! Tomato plants :)