The ECE community is involved in this movement in several ways. One is through the Nature Action Collaborative for Children. http://www.worldforumfoundation.org/wf/nacc/index.php
The NAEYC Journal Young Children has been publishing articles for many years about the value and need for young children to spend time outdoors and learn about nature and the environment. There are some terrific books written by Ruth Wilson about young children and nature as well. I hope this gives you some leads to explore further :)
Thank you for your response. I was thinking more in lines of talking face to face with educators at conferences...sharing experiences and books, articles etc. I am often surprised at the number of teachers who are still hesitant about the outdoors and how to bring it in to the classroom and the endless possibities outside the classroom. Except for Nature Explore I have yet to see advocates at these conferences. Even when I review the keynote speakers and workshops there are very still very little, if any, regarding this topic.