I have 2, to recommend; these recommendations came to me from a successful designer and user experience expert.

 - http://www.colourlovers.com/

   > ... a creative community where people from around the world create
and share colors, palettes and patterns, discuss the latest trends and explore colorful
articles... All in the spirit of love.

and

 - http://kuler.adobe.com/

   > ... discover Adobe® Kuler™ — the web-hosted application for generating color themes that can inspire any project. No matter what you're creating, with Kuler you can experiment quickly with color variations and browse thousands of themes from the Kuler community.

I have used *kuler* myself and enjoyed what it outputs and how it works.