e-nature
Wow—it's the Audubon Field Guides online! There are over 4,800 animals and plants pictured on these Web pages, drawn from the well-known print guidebooks. The content includes: Amphibians, Birds, Butterflies, Fishes, Insects, Mammals, Reptiles, Seashells, Seashore Creatures, Spiders, Trees, and Wildflowers. Each specimen is pictured in a small thumbnail photo. If you click on it, you'll get a larger picture plus lots of information on the creature or plant.
http://www.enature.com/