How to Save Tomato Seeds

I found this on a website about seed saving, and I'm amazed! I might try this so that I can use some of my seeds from this year.

Tomato - Lycopersicon esculentum
PLANT: Separate varieties with short styles (most modern varieties) by at least 10 feet. Varieties with long styles (heirlooms and older varieties) need at least 100 feet to ensure purity. If solitary bees are prevalent, separate all varieties at least 100 feet and place another flowering crop between.
FLOWER: Tomatoes produce perfect, self-pollinating flowers. Anthers are fused together into a little cone that rarely opens until pollen has been shed and the stigma pollinated. (Older varieties with wild tomatoes or L. pimpinellifolium in their genetic ancestry may have stigmas that stick out beyond the cone containing the anthers. Varieties with this trait can be identified by looking closely at mature flowers and need to be treated accordingly.)

SELECTION TRAITS: Tomato is the most popular vegetable in America and hundreds of the genes have been mapped. Those of immediate importance for home gardeners include: Plant size: Determinate varieties, r; b ush varieties, r; dwarf varieties, r. Leaf Shape : Potato-type leaves, r. Disease resistance : Leaf mold resistance, r; fusarium wilt, race 1 and race 2, D; verticillium wilt, D; alternaria, D; tobacco mosaic, D; nematodes, D. Ripening : prevents green shoulders, r; prevents ripening and is found in Longkeeper, r; produces parthenocarpic fruits which do not need to be pollinated. Tomatoes without seeds can be produced in weather too-cold for pollination to take place, r. Fruit color - produced by the combination of flesh and skin colors:
red: pink flesh, r covered by a yellow skin, r
pink: pink flesh, r and colorless skin, r
crimson: bright, purplish-red flesh, r and yellow skin, r
purple: bright, purplish-red flesh, r and colorless skin, r;
yellow: yellowish flesh, r and yellow skin, r
white: yellowish flesh, r and colorless skin, r
orange: reddish-orange flesh, D and yellow skin, r
HARVEST: If possible, allow tomatoes to completely ripen before harvesting for seed production. Unripe fruits, saved from the first frost, will ripen slowly if kept in a cool, dry location. Seeds from green, unripe fruits will be most viable if extracted after allowing the fruits to turn color.
PROCESS: Cut the tomato into halves at its equator, opening the vertical cavities that contain the seeds. Gently squeeze out from the cavities the jelly-like substance that contains the seeds. If done carefully, the tomato itself can still be eaten or saved for canning, sun-drying or dehydrating.
Place the jelly and seeds into a small jar or glass. (Add a little water if you are processing only one or two small tomatoes.) Loosely cover the container and place in a warm location, 60-75° F. for about three days. Stir once a day.
A layer of fungus will begin to appear on the top of the mixture after a couple of days. This fungus not only eats the gelatinous coat that surrounds each seed and prevents germination, it also produces antibiotics that help to control seed-borne diseases like bacterial spot, canker and speck. After three days fill the seed container with warm water. Let the contents settle and begin pouring out the water along with pieces of tomato pulp and immature seeds floating on top. Note: Viable seeds are heavier and settle to the bottom of the jar. Repeat this process until water being poured out is almost clear and clean seeds line the bottom of the container. Pour these clean seeds into a strainer that has holes smaller than the seeds. Let the excess water drip out and invert the strainer onto paper towel or piece of newspaper. Allow the seeds to dry completely (usually a day or two). Break up the clumps into individual seeds, label and store in a packet or plastic bag.