Classification
Click on the link below for an excellent site about the basics of "Classification -Taxonomy".  Click on "Studies & Methods." Then click on Taxonomy. Following your reading of this topic click on the additional menu items on the left side of the page (Labels, Kingdoms, Humans and Pre-humans).
http://www.biology4kids.com

The following site is a great one for information on all types of animals. It provides printable pictures, outlines of animals to color, and the scientific classification of the animals. Give it a try.
http://www.enchantedlearning.com

This next site is an outstanding one for "Classification." There are interactive exercises as well as additional 'links" to other sites for more in-depth study. Try it out!

http://www.howe.k12.ok.us/~jimaskew/bclasfy.htm