Greenpeace - I've been a member since I was10 years old.
I really don't know the good environmental website links. I had been a member of the Nature Conservancy but then the Washington Post broke the stories on how the executive members had been stealing money, working with terrible corporations like Exxon, and had actual board members from the worst killers of all corporations. It's one of saddest days on Earth. The people we entrusted to save our Dolphins, animals, planet.... are actually and secretly took over the Nature Conservancy and began killing what they swore to protect.