Causes of Color takes a novel view of color theory in very memorable fashion. Color is made [additive theory], lost [subtractive color theory], and and moved [color transformation]. Cause of Color explores many natural phenomena associated with color perception including color blindness and illusions. This is a well designed website using color with savvy.
Color Matters makes the pun and runs with it with a site filled with all the aspects of color and color theory. Some of this material is what you will see in your Color class - but large portions of the site are unique and very informative about the sociology and play of color in all aspects of life.
Color Physics provides the science background of color and light. Hang onto this site for its insights on how media and technology shape color.
Color Systems provides a wealth of history and knowledge about color. Going back to Greek philosopy to the discoveries of Newton and Leonardo to modern science and art - often moving in parallel but not necessarily mutually acknowledged synchrony. Absolutely fascinating.
Color Worqx is a very rich and lavishly illustrated intro to every aspect of color theory. If you get stuck elsewhere come here from a different point of view. Be sure to try Peter Piper's Palette Picker.
Color Arts takes a look at color in arts and ideas. It provides a history of how alternately science and then arts stimulated the development and use of colors. Ihav e launched you into the middle of things, so explore the menus and tabs. This is another must see website for anyone interested in color.