Soak the beans in 2 quarts of cold water overnight, or in 2 quarts of boiling water for an hour or two. After soaking, or the next day, bring the beans to a boil over medium high heat. Reduce the heat, so the beans merely simmer. Cover and simmer for half an hour Then add the margarine or bacon, salt and pepper. Cover again and simmer for another 45 minutes to an hour. The beans should be tender and fragrant. Bite into one to see if it cooked through. When they are tender, they are ready to serve.