Vegan Represent -- oh, but you'll thank me
VeganHealth.Org an extensive nutrition FAQ dedicated exclusively to vegan health, run by Vegan Outreach.
Dr. Michael Gregor maintains an extensive and broadly informative site that's well worth exploring. If you'd like a good beginning point, however, I'd suggest scrolling down the main screen, select Online Talks, followed by Optimal Vegetarian Nutrition.
Key Points --
-- Eat Dark Leafy Greens, Beans, Fresh Fruit and Whole Grains, every day
-- As many vegetables as you can, every day
-- Drink five(5) 8oz glasses of water a day. Consider drinking Green Tea every day (but not with meals).