Some good reads :
http://www.wetwebmedia.com/marine/index.htm
http://saltaquarium.about.com/index.htm?terms=saltwater
(look at the subjects on the left)
http://saltaquarium.about.com/cs/bc...terms=saltwater
http://saltaquarium.about.com/blqa.htm
Good stuff regarding foam fractionation. Even if you are rearing fish only, aim to get a good one.
http://saltaquarium.about.com/libra...ly/aa052200.htm
A good site with images to help you ID fishes, corals, plants and invertebrates.
www.liveaquaria.com
Other sites just list out the names and you are left dumbfounded.