To Buy: 
Fresh green soy beans are called edamame. They are cooked in their pod and usually frozen. Available from Asian stores.  Most soy beans are sold dried. Buy them from a health food store or shop with a high turnover of produce. 
To Store: 
Store in an airtight container for up to 12 months. 
Tips & Tricks: 
Because the bean has a high protein content there are numerous soy products emerging onto the market for vegetarians. Always examine the ingredients - soy or not, with all the additives it may be no better than spam!
Cooking Tips: 
Always soak soy beans for at least 12 hours. Cook 1 cup of beans to 4 cups water for up to 6 hours. To improve the digestibility of the bean add some kombu to the water.  
Bean salads are easier to digest with a vinegar dressing added to it at least 1/2 hour before serving.