Organic and Heirloom Seeds
In this list you'll find links to seed companies that I recommend and buy from. Most of them specialize in heirloom or antique seeds. All of them have further information on their websites about growing vegetables, herbs and flowers, and many of them are like mini-encyclopedias of plants. Check 'em out, and help support small seed companies, many of which are family owned.
Baker Creek Heirloom Seeds--specializes in non-GMO, open-pollinated, heirloom garden seeds. They also publish The Heirloom Gardener magazine.
Botanical Interests--specializes in non-GMO, untreated, organic seeds--many heirlooms
Renee's Garden--Heirloom & Gourmet Vegetable, Flower and Herb Seeds--owned by Renee Shepherd. An especially gorgeous website, with articles on how to grow vegetables, herbs and flowers and delicious recipes. One feature I especially love are the lists of recommended flowers and plants. For example, recommended plants for an Heirloom Cottage Garden, Seeds for an Endless Salad Garden, etc.