Biomes of the World
http://www.mbgnet.net/
This site has a wealth of valuable information. From the Missouri Botanical Gardens.
Tour of Biomes
http://www.cotf.edu/ete/modules/msese/earthsysflr/biomes.html
Developed by the Center for Educational Technologies in conjunction with Wheeling Jesuit University and NASA's Classroom of the Future. Excellent site- easy to use format with great information. Nicely organized.
World Biomes.com
WorldBiomes.com is a site covering 5 of the major world biomes. This reviewed site provides you with various sub-divisions and examples of the 5 types of biomes and their distinguishing features.
World's Biomes -- From University of California at Berkley, this is an introduction to the major biomes on Earth.
Biomes of the World: -- From Radford University, Department of Geospatial Science
World Biomes (Kids Do Ecology): Not just for kids!
PBS Learning - Biomes: From PBS, click on "launch" to explore various biomes.