Zolfini beans are dried pale yellow heirloom beans grown in the Tuscany region of Italy. These little beans can be used for bean soup or any number of dishes with and without meat. Zolfo is Italian for sulphur the word for which the bean was named. Use Zolfini beans in any recipe that calls for cannellini or other white beans. Zolfini are are a time and water intensive crop so production is small.
These beans will probably be hard to find outside of Italian specialty stores and some farmer's markets. You may want to buy some seed and grow your own. You can purchase organic seed here from UprisingOrganics.com.
Zingerman's has a good blog post about a traditional Tuscan dish made with Zolfini Beans, called Ribollita. You can follow that link for the recipe and more information.