Color Theory in Science and Art: Ostwald and the Bauhaus (Philip Ball and Mario Ruben).
http://iwrwww1.fzk.de/ruben/pdf/color.pdf

Visual Perception and Aesthetics (Steven Ståhlberg).
http://www.androidblues.com/visualperception.html

Color Vision and Art (Webexhibits).
http://webexhibits.org/colorart/

Color Printing in the Nineteenth Century.An Exhibition at the Hugh M. Morris Library University of Delaware Library, Newark, Delaware, August 27 - December 19, 1996.
http://www.lib.udel.edu/ud/spec/exhibits/color/

Exploring the Color Image (Omens, W):
http://www.kodak.com/US/plugins/acrobat/en/motion/education/introduction.pdf
http://www.kodak.com/US/plugins/acrobat/en/motion/education/color_light.pdf
http://www.kodak.com/US/plugins/acrobat/en/motion/education/character_of_color.pdf
http://www.kodak.com/US/plugins/acrobat/en/motion/education/kodak_color_films.pdf
http://www.kodak.com/US/plugins/acrobat/en/motion/education/problems_in_color_photo.pdf
http://www.kodak.com/US/plugins/acrobat/en/motion/education/perception_reading.pdf
Online book on colour in photography, after Raplph Evans' Color as Seen and Photographed.

"Colour harmony" tools

Color Wheel Pro - allows you to compare color schemes generated using the conventional artists colour wheel and the RGBCMY wheel.  The colour schemes can be previewed as web pages, packaging or logos.

http://www.color-wheel-pro.com/index.html  (free trial)

Color Harmony Chooser. (gives the two other triad colours on a 12-colour wheel)
http://www.interlacken.com/rfp2000/colorpik.htm (online)

Palette Master (Nebulus designs).
http://www.nebulus.org/freebies/coders/palette/ (online)

(There are many more of these devices available both online and for download, but most use only the naive RYB colour wheel, and so are essentially useless.

Colour scheme generators