I am on the education committee for an organization called Organic Athlete that promotes veganism through athletic events. The main person behind it, Bradley Saul is very hard-working and ambitious about what they can achieve. Recently I helped with their Sports Nutrition Guide. While I do not agree with all of it (mostly the raw food, anti-fake meat wingnut stuff), it is still a very good resource. Check it out here:
Organic Athlete Guide to Sports Nutrition