KULER - Explore, create and share color themes
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.
http://kuler.adobe.com/#themes/rating?time=30
http://www.adobe.com/products/kuler/

Color Jack
ColorJack is an online Color Scheme Generator used by Graphic Designers, Interior Decorators, and many other people from around the world. Currently available in 13 languages.
http://www.colorjack.com/
http://www.colorjack.com/sphere/

Color Blender
ColorBlender is developed by Kim Jensen and can best be described as a "version 2.0" of my ColorMatch 5K tool developed for the Danish 5 KB webdesign competition in 2001. The tool is completely free to use, however, I highly appreciate even the smallest donation, as this help me finance website hosting and continous development of this tool and others.
http://colorblender.com/

Easy RGB
This site provides information and services related to color technology.
During the years it has become a popular source of technical and commercial information about colors, color science and color programming techniques.
http://www.easyrgb.com/

Logo Orange
Note that the conversions in this color codes chart are best described as "nominal". They will produce an invertible conversion between the RGB code and a subset of CMYK; that is, one can take an RGB color code and convert to certain CMYK colors, and from these CMYK colors obtain the matching, original RGB codes. However, conversion of CMYK colors to RGB cannot be reversed; this means, given a CMYK color code which is converted to RGB, performing the former conversion may not give the original CMYK color. In addition, CMYK colors may print differently from how the RGB colors display on a monitor. There is no single "good" conversion rule between RGB and CMYK, because neither RGB nor CMYK is an absolute color space.
http://www.logoorange.com/color/color-codes-chart.php

Screenalicious
Trying to keep up with the ever changing design trends online? Too many design related RSS feeds? Getting too complicated to browse for inspiration on a regular basis? No need for any hassle anymore. Just subscribe to Screenalicio.us RSS feed and it will all be taken care of. Screenalicio.us is the web's new premier source for showcasing excellent websites and inspire artists all alike to create spectacular work of their own. We have the largest collection of websites you will ever lay your eyes on, and it keeps on growing every day.
http://www.screenalicious.com/

Colour Lovers
COLOURlovers™ is a resource that monitors and influences color trends. COLOURlovers gives the people who use color - whether for ad campaigns, product design, or even in architectural specification - a place to check out a world of color, compare color palettes, submit news and comments, and read color related articles and interviews.
http://www.colourlovers.com/

Colour Mod
ColourMod originally made its debut as one of the most flexible, not to mention, good looking, DHTML Dynamic Color Pickers out there. Since then ColourMod has become even more robust, with room to expand beyond imagination.Currently, ColourMod comes in many different juicy versions. Each version is tailored to fit your specific needs and desires. From colour conversions on your desktop, to colour picking on the web, there is something for you. To find out more information about each of these versions of ColourMod, please select a ColourMod version from the left.
http://colourmod.com/

Page Painter
When a local web page is opened in the PagePainter browser, the page responds to point and click color changes. Testing colors and color combinations on your own web site layout is as easy as painting on a canvas. Click on any element on your web page to change its color without changing the source code of your page. Save different colored versions of the same web page and compare them in PagePainter before commiting changes to code.
http://www.pagepainter.com/