Below find a brief Internet pathfinder that will lead you to information-rich sources on biomes and ecosystems.

University of California at Berkeley Introduction to Biomes of the World
A thorough and authoritative web site created by UC Berkeley. It is searchable, has lots of images, it includes a FAQ and a glossary.
http://www.ucmp.berkeley.edu/exhibits/biomes/index.php


United States Environmental Protection Agency’s High School Environmental Center
Ecosystems Page

The title says it all: great research site for high school students studying biomes and ecosystems.
http://www.epa.gov/highschool/ecosystems.htm


The World Wildlife Federation (the other WWF) Ecoregions Site
Gives abundant information on the species in many ecological regions by geographic area. Has terrific information on human impact in these regions.
http://www.panda.org/what_we_do/where_we_work/ecoregions/


Radford University’s Introduction to Biomes Site
A good place to review the basics.
http://www.runet.edu/~swoodwar/CLASSES/GEOG235/biomes/intro.html


What’s It Like Where You Live? Missouri Botanical Gardens Biomes Site
Scientists at the Missouri Botanical Gardens generously share their knowledge about biomes.
http://www.mbgnet.net/


High School Students in Oregon Show Off Their Biome Research
Check out what some high school students did on biomes. This is not something you would site, but may give you some good ideas of what people at your level can do.
http://ths.sps.lane.edu/biomes/index1.html


A Research Guide for Students’ Biomes Page
One of many online sites published by ‘areasearchgiude.com’. Looks rich in information. Caution: It's very difficult to find credit for the people who put together. This could be a bad sign. How do we know if this information is authoritative or not?
http://www.aresearchguide.com/biomes.html