Aye-Aye's Primate Primer - Filled with good information and pictures of a variety of primates.  

San Diego Zoo - Good background information for teachers about different monkey species and behavior. 

Planet Monkey - This site offers a variety of information and photographs.

Monkey Sounds - This site has downloads available of different monkey sounds.

Monkeys-Monkeys! - A site with good, basic information, photographs, and links.

Caps for Sale by Esphyr Slobodkina.
This is the classic tale of a peddler, his caps, and some monkeys!

Chimp and Zee by Catherine and Laurence Anholt.
Two little monkeys get into trouble in Jungletown!

Fifty Red Nightcaps by Inga Moore.
A little boy tricks some monkeys into returning his 50 nightcaps.  A great book to use in a language arts lesson to compare to Caps for Sale by Esphyr Slobodkina.

Five Little Monkeys Jumping on the Bed by Eileen Christelow.
This familiar rhyme is fun for young children.

Five Little Monkeys With Nothing to Do by Eileen Christelow.
The same five monkeys get into trouble when trying to help their mother.

How Mr. Monkey Saw the Whole World by Walter Dean Myers.
The story of a selfish buzzard and a monkey who teaches him a lesson.

I Like Monkeys Because...by Peter Hansard.
A simple book which contains some true facts about monkeys.

Monkey Do! by Allan Ahlberg.
A little monkey leaves the zoo and has a fun-filled day!

The Monkey and the Crocodile by Paul Galdone.
An Indian fable in which a monkey outwits a crocodile.

Monkey King by Ed Young.
The Chinese legend of Monkey and his adventures with Dragon King and Jade Emperor.

Monkey Mo Goes to Sea by Diane Goode.
A little boy takes his pet monkey aboard a ship.  The monkey is warned to "act like a gentlemen" by the boy's grandfather.  The monkey, however, finds some mischief!

Monkey for Sale by Sanna Stanley.
Two little girls work hard at a Congolese market day to buy a pet monkey.

Monkeys of Central and South America and Monkeys of Asia and Africa (two separate books) by Patricia A. Fink Martin.
Wonderful nonfiction books which include lots of information and photographs.

One Monkey Too Many by Jackie French Koller.
Some monkeys get into trouble by not following directions.  A good book to use in a math lesson on adding one.

So Say the Little Monkeys by Nancy Van Laan.
This story is based on  tale from the Brazilian Rainforest about tiny monkeys procrastinating!

The Turtle and the Monkey by Paul Galdone.
A turtle and a monkey fight over a banana tree.  Which of these animals is more clever?

Water Hole Waiting by Jane Kurtz and Christopher Kurtz.
A young monkey must wait his turn to get a drink of water, while being careful of the other animals in the jungle.