ColorBlender.com - free online color matching toolbox

This has to be one of the coolest online tools I have seen for web and print designers in a while. You simply enter your preferred starting color using the color picker and a matching six-color palette will automatically be calculated.

I have seen books that provide sample palettes to use and online tutorials that present the theory behind the various color blends, however, nothing compares with the interactivity behind this site's tool.