Go to this link tshirt.htm and look at some of the student solutions to a color theory assignment I designed for a course I built - where practical or experimental design challenges followed exercises and lecture- in this case:
"Four T-shirt Designs -
Create four designs using the t shirt template provided, or use one of your own. Media is open.
Color schemes
monochromatic, complements, split complements, triadic"
You can see the same design interpreted with four different schemes -
while you are there check out /colortheory.htm
specifically the links towards the bottom - some of my favorites include the auto gen color schemer: colorschemer.com/online.html
and here is another http://www.wellstyled.com
If you google around you will find more robust versions - J