The library is not just about sharing books. Getting children involved with the library and borrowing books, rather than buying them, is an enviro friendly action that will stay with them for their life. Also the library is a great place for finding magazines, CDs, audio books and videos.
Also here are some great books that teach environmental ideas to children:
A Kid's Winter EcoJournal: With Nature Activities for Exploring the Season by Toni Albert and Margaret Brandt.
Ecoart!: Earth-Friendly Art and Craft Experiences for 3-To 9-Year-Olds (Williamson Kids Can! Series) Laurie Carlson.
Keepers of the Earth: Native American Stories and Environmental Activities for Children by Michael J. Caduto and Joseph Bruchac.