Gardening With Kids - Good site for teacher background information as well as experiments on leaves changing color.

State University of New York - More good background information on why leaves change color.

KidZone - The information at this site is presented in a simple manner for children to understand the process of leaves changing color.  Their are also activities and leaf photographs.

The Miracle of Fall - A collection of sites which lead to lesson plans and information on fall related topics.

NASA - Explains the first day of Autumn with an animated video.

MaineFoliage.Com - Includes a great animated movie on how leaves change color (in the Kids' section).

The Great Plant Escape - This site is designed for children and has information specifically on how leaves work for a plant.

Autumn Leaves (Preparing for Winter) by Gail Saunders-Smith.
Provides information on the different types of leaves.

 Backyard Explorer Kit: Leaf and Tree Guide/Leaf Collecting Album (Backyard Explorer) by Roan Beame.
A good reference book for different types of leaves.

Fall Leaves Fall! by Zoe Hall.
Two young children describe their favorite time of year...the fall!

Fall is Not Easy by Marty Kelley.
Simple text accompanies the illustrations of a tree changing through the year.

Fall Leaves (My First Hello Reader! Series) by Mary Packard.
This easy reader includes activities which can be done in fall leaves.

Free Fall by David Wiesner.
This wordless picture book follows a little boy's dream as he travels on a leaf.  Good inspiration for children to write about their own journeys.

I Am a Leaf by Jean Marzollo.
An easy reader which follows the life cycle of a leaf.

Look What I Did with a Leaf! by Morteza E. Sohi.
This book has wonderful examples of scenes and animals that can be created by using dried leaves.  Specific instructions are given on drying the leaves and how to create different effects.

Red Leaf, Yellow Leaf by Lois Ehlert.
This beautiful book follows the changes of a tree as it grows. 

Why Do Leaves Change Color? by Betsy Maestro.
This "Let's Read and Find Out Science" book provides great information on leaves and their changing colors.