Besides broadcasting Barney, Big Bird, and other kid-favorite characters, PBS Teachers is chock full of cool interactive teaching tools. Thay have everything indexed on their thematic teaching list. While learning about Africa, kids will be guided by Femi through a Swahili folktale, the thumb-piano, and making an African mask.
If you're teaching about reptiles, kids can click their way through the anatomy of a crocodile. In a literature class, kids can use PBS' storytelling-tool to make a "movie trailer cut from stone."
Cartoon, crocodile and stone images from pbs.org.