San Diego Natural History Museum
San Diego Natural History Museum: Shark School: From Shore to the Deep Blue Sea
Small site provides information on different types of sharks: mako, thresher, hammerhead, horn, and others.
Other
Fishin for Facts Library
A comprehensive site that includes a wealth of information on whales, sharks, penguins and squid.
Merriam-Webster
Merriam Webster: Dictionary Illustration: Types of Sharks
Labeled illustration of five types of sharks: mako, tiger, thresher, hammerhead, and great white.