Note - special section for kids at bottom of post
I wrote two articles about them - one regarding their natural history, and the other their conservation. I hope you'll check them out!
I have had the amazing opportunity to snorkle with them, and let me tell you - there are few experiences as awesome as being side by side with an extremely large yet extremely gentle marine mammal like this. And even more amazing to me is that they seemed to seek out human company. At times they would swim into the "off-limits" zone (meaning off-limits to human divers, to afford them a peaceful human-free zone when they wanted it), only to turn around and come back to me once they realized I was no longer with them!
If you are interested in manatees and conserving them, you must check out this organization. I hope you will sign up to receive their action alerts, helping manatees whenever possible.
They also have the option to "adopt" a manatee - these make great gifts!
Manatee Kid Zone
The Save the Manatee site has a great page just for kids! And another for educators! Whether you're a teacher looking for classroom materials, or a parent looking for fun activities to do with your kids, you're sure to find something usable! Here and here are links to a bunch of free manatee stuff. Enjoy!