Pantone
The granddaddy of color companies. PMS stands for Pantone Matching System.
Pantone
Color Scheme Generators
Most online color generators are created for web design, but work just as well for print. Find the colors you like and use a Pantone swatch book to match the hues. If you don't have a swatch book, you can use the eyedropper tool in Photoshop to get an approximate CMYK breakdown.
Color Scheme Designer
Kuler
Colorspire
These sites allow you to upload an image and produce a palette from its colors.
Pictaculous
Color Hunter
Color Palettes
Its can be difficult visualizing color combinations in your head. Seeing them in use is a helpful means of selecting hues.
Colour Lovers
Design Seeds
For the Love of Color
Color Collective
Swiss Style Color Picker
Misc. Color Sites
When searching for websites concerning color, don't limit yourself to just graphic design. Investigate fashion, painting, ceramic glazes, art history, interior decoration, etc. There are many talented people out there utilizing color into their respective mediums and fields.
Plenty of Color
Colour Wheels, Charts, and Tables Through History
Video
Color Theory: Hue and Saturation
This will make your brain hurt, but is very interesting in comparing RGB and CMYK.
The Truth About The Color Wheel
Audio
Radiolab is a science-based program heard nationally on NPR.
Why isn't the Sky Blue?
