I am glad to introduce our visitors to new color palettes website, which was just launched - http://www.colorotate.org.
It has new interesting and involving 3D interface, I would recommend to try it out.
Also it offers to build a community around the palettes, meaning to share created palettes with each other.
They have several plugins to synch the palettes with Photoshop.
This website also contains a plenty of information on colors fundamentals, history and phisics.