Jonathan Bird's Blue World is an Emmy award winning educational program that explores the wonders of the world's oceans.
The program airs on public television, but the website also has webisodes on the site for you to view. They also have an educators' section with study guides for each episode, sea stories and web links. You can even book him to come to your school and do a presentation (for a fee). He is very dynamic and you can see an example of one of his presentations.
They have updated their website and added new science curriculum-based episodes, advanced search, and new functionality for teachers using Blue World in the classroom.
New segment: Humpback Whales!
Every year, Humpback whales in the North Atlantic make a long migration down to the Caribbean to have their calves in warm, calm water. Many of these whales go to one particular area called the Silver Banks near the Dominican Republic. Jonathan spends a week in the Silver Banks filming whales underwater, and you won't believe how close he gets to the whales, and the exceptional behaviors he observes! Watch now!
On a side note, I actually went to college with Jonathan at WPI. He was two years ahead of me, but was in a band with a friend of mine. He's a great guy and it's great to see another engineer doing educational work.
Explore the Blue - lessons about water for all subjects - from Discovery Education (free resource).
USGS Education Resources - free resources for teachers - including resources about water
Great Earth Day Resources for Educators
NASA Eyes on the Earth - vital signs of the planet