I wrote an Instructable on this topic and now have turned it into a video. This video explain the process of fermentation of tomato seeds and why it is needed. It shows you all the steps from collecting the seeds to storing them.
Please visit my very active blog at The Rusted Garden for more gardening information.
I have over 50 garden videos and several recipe videos for your garden produce at my YouTube Channel My Tomato and Vegetable Garden. Please visit.