Cook with Chocolate
The World Cacao Foundation is an organization dedicated to promoting sustainable cacao-growing practices, both by ensuring fair wages for farmers and encouraging environmentally responsible and effective growing methods. Lots of resources and information can be found here, including teaching materials, information on scientific research programs, and initiatives addressing child labor in West Africa. Fairtrade International offers information on Fairtrade labeling, what it does and doesn't mean, and standards for labeling and certification.
Meet Like-Minded Chocolate Folk
Buy Some Chocolate and/or Accoutrements
For chocolate itself, World Wide Chocolate carries every major brand of high-quality chocolate I've ever heard of, and a bunch that I haven't. Blocks, chips, cocoa powder, gift baskets...it's pretty much all there. Good luck leaving the site without buying something.