ColoRotate is a free online service that has some similarities to Adobe Kuler, but is different in that it's in 3D. Users can browse color palettes, create new palettes, and share palettes with others in the ColoRotate community.
Using ColoRotate 3D interface, you can quickly see the multidimensional nature of your colors and the relationships between colors in a way that matches how your eye and brain perceive color and change your colors one at a time, blend two colors together, or transform a full palette of colors all at once with contrast and color joysticks — adjustments that previously have been beyond your reach. With ColoRotate’s quick drag-and-drop you can adjust hue, brightness, and saturation. Import and export in Adobe Swatch Exchange (ASE). Soon, you’ll be able to save even more time with a Photoshop Plugin.

You can also post on-line your palettes, and tag palettes to engage with the ColoRotate community, or discussions. In the future, look for features like comments and ratings.
ColoRotate has an intuitive interface that eliminates the need to memorize or jot down color combinations or numbers. Indeed, you can traverse across an open three-dimensional color space and choose (or design) the color palette that fits your needs. In the process, you can uncover color relationships that give your designs an aesthetic balance that will please the most discriminating eye.

I use kuler and find it very good especially its website service to extract the colors from an uploaded photo. Great help when determining a color scheme for a new client.
1 thing about kuler that troubles me is getting the hex of the colors which needs more than 1 step e.g. click on #, paste it in a textfile and copy the one I want
I love the amount of details you gave in your instructions through this article. Looking forward to more from you.
Regards,
photo colorization
I second Kuler myself. This is really confusing to me. Maybe it appeals to some people though. Just too much going on on screen, too many colours being sucked into my eyeballs and then the 3D element makes my mind wonder even more...