U. of Wisconsin Sea Grant: Great Lakes Education and Outreach
link
This site seems to be aiming to have all the information you'd need to understand the geography and ecology of the Great Lakes region. Most of the information is aimed at adults, but would be accessible to an interested child. There is also a Parent/Kids section with information on the birds, fish, frogs, and more of the Great Lakes.
Don't miss the Paddle to the Sea Google Earth app, it's meant to accompany Holling C. Holling's classic storybook, and has links to extra information and activities to accompany each chapter.
