Vegetable Seed Saving Handbook
Seed Savers Exchange
The preeminent seed saving organization, whose members share over 1,000 heirloom varieties of vegetables, fruits and grains. Probably the greatest single heirloom seed-saving resource.
Heirloom Seed Swap
This new (Mar 2010), completely-free seed-trading website allows members to post 'ads' for homegrown heirloom seeds they have available to trade or sell. Registration requires only a username and email (the latter for confirmation puropses only). A great place to share seeds and build up your collection.
Vegetables and Fruits: A Guide to Heirloom Varieties and Community-Based Stewardship, Resource Organizations
Compendious compilation of heirloom seed saving and preservation organizations, companies, individuals, etc. As complete a listing of seed saving groups as exists.
Fedco Seed Cooperative
Heirloom seeds and gardening supplies... "We offer a large selection of certified organic cultivars and regional heirloom varieties." A broad selection and good prices make Fedco a favorite of many organic gardeners (my thanks to reader Sarah Moore for reminding me of this one).
"Heirloom, Untreated Open-Pollinated Varieties for Sustainable Agriculture" from John Jeavons' Biodynamic gardening group. An excellent resource for good-performing, heirloom garden seeds.
Territorial Seed Company
Heirloom seeds and live plants... "Agriculture and seeds provide the basis upon which our lives depend. We must protect this foundation as a safe and genetically stable source for future generations."
Victory Seed Company
"...a small, family owned and operated organization that works to preserve plant varieties by locating, growing, documenting and offering heirloom and rare open-pollinated seeds to home gardeners."
Reprinted from Vegetable Seed Savers Handbook, Jack Rowe 1998, howtosaveseeds.com