Tim,
Yes, most seeds packaged for this year will geminate next year. Here's a link to give you an idea of what to expect.
http://www.growingyourownveg.com/veg...dviability.php
Saving your own tomato seeds is easy. Why don't you do a trial run with a couple or bought tomatoes.
Squeeze out the seeds into a pint jar with as much juice as you can get. Cover the jar and put it in a warm place for 3-4 days until a white mold/slime forms on top caused when the microbes have finished eating the jel from around the seeds as the jel is a gemination inhibitor.
At the kitchen sink pour the seeds into a larger container [like a half-gallon mason jar] and then use the spray nozzle on high pressure to agitate the seeds and stire them up real good. The seeds will sink to the bottom and you can pour the water off of them. Do this twice.
Then pour the seeds into a small hole strainer over the sink and wash them again with spray nozzle.
Write the tomato name on a paper plate and with a quick motion, flip the strainer over and frap the seeds onto the plate. Spread out the seeds and put the plate in a warm dry place for the seeds to dry out.