Geology Maine Geological Survey - geology of Maine. Astronomy Windows to the Universe- a great site for astronomy, earth science, biology, etc. You could spend hours surfing around this University of Michigan site. Estuaries Salt Marsh Field Trip - Take a virtual trip to a salt marsh. SUNY Rocky Shore Page - photos of many, many marine organisms and cool facts about them.
Most examples are from the Pacific, but the information still applies to our coast.
Gulf of Maine Council - Look at awesome undersea maps, learn about the Gulf of Maine Watershed, deep basins, coastal ecosystems, currents, etc. Gulf of Maine Aquarium - More Gulf of Maine related stuff. Aquatic Network Links - tons of ocean links brought to you by the Aquatic Network. Intertidal Zone Links - links to sites relating to the intertidal zone. MBGNet Water Cycle Page - goes over scientific principles involved, cloud formation, etc.