Tutorials, Experts, Problems, and Message Boards

Mad Scientist Network - Online expert answers to your science questions in over twenty-five areas of science, and you get to state the level at which you are studying so the response is appropriate to your level of information. Also has archives so you can check previously asked and answered questions
http://www.madsci.org/current.html

Ocean Link - marine science information and interaction web site, including Ask a Marine Scientist and links 
http://oceanlink.island.net/

Substantive Marine Biology Sites

Aqualink - information and search engine dedicated to freshwater and marine fish, aquatic plants, goldfish, reef systems, invertebrates and coral
http://www.aqualink.com/

Cephalopod Page - octopus, squid, nautilus - information, photographs and links
http://is.dal.ca/~ceph/TCP/index.html

Fish Frequently Asked Questions
http://www.wh.whoi.edu/homepage/faq.html

Marine Watch - quarterly journal of marine events
http://www.marinewatch.com/index.html

Ocean Link - marine science information and interaction web site, including Ask a Marine Scientist and links 
http://oceanlink.island.net/

Ocean Planet - online Smithsonian exhibit
http://seawifs.gsfc.nasa.gov/ocean_planet.html

Shark Bytes - Internet Sources of Information on Sharks, Skates, Rays and Chimaeras
http://www.elasmo.org/links.htm

WhaleNet
http://whale.wheelock.edu/

Woods Hole Oceanographic Institute
http://www.whoi.edu/index.html

Links

Icythyology Web Resources
http://www.biology.ualberta.ca/jackson.hp/iwr/iwr.html