Ecosystems – Geography for Kids Chapter 9: The Biosphere has great information about biogeochemical cycles (carbon, nitrogen, phosphoros etc), food chains and biomes.

Australia’s eight major ecosystem types are described at Gulliver Productions’ site.

Library ThinkQuest has information about the ten major biomes and how humans have affected ecosystems.

Windows to the Universe is an award-winning site with information about biomes and ecosystems.