The Ocean Planet (Smithsonian)
http://seawifs.gsfc.nasa.gov/ocean_planet.html

Oceans (The Evergreen Project) This site has MANY excellent links.
http://mbgnet.mobot.org/salt/oceans/index.htm

Ocean World (very cool)
http://oceanworld.tamu.edu/

WhaleTimes SeaBed
http://www.whaletimes.org/

Where can I get Answers to Questions about oceanography
http://www.whoi.edu/info/where-answers.html

Coral Reefs
http://www.yoto98.noaa.gov/books/reefs/reef1.htm
http://coral.aoml.noaa.gov/