Here are few books that might be useful. The first two are available from inSpirit: The UU Book and Gift Shop.
Nurturing Children and Youth: A Developmental Guidebook by Tracey L. Hurd (Boston: Unitarian Universalist Association, 2005)
Last Child in the Woods: Saving Our Children from Nature-Deficit Disorder by Richard Louv (Chapel Hill, NC: Algonquin Books, 2005)
Rituals and Patterns in Children’s Lives, edited by Kathy Merlock Jackson (Madison, WI: Popular Press, 2005)