Free jQuery Color Picker: ExColor
ExColor is a Free jQuery color picker plugin to select colors from a Photoshop-like color picker.
Can be appended to form input text fields and allow the user to choose his desired color, instead of entering the color code.
A custom color picker skin creator (wizard) is also available to customize as per your needs.
Nice color picker, check this jquery one out: http://www.websanova.com/plugins/websanova/color-picker