A color picker, or color chooser is a utility, usually found within graphics software or online, used to choose colors or create color schemes.
You can find a number of color picker tools on the internet but when it comes to customize / skin a color picker plugin, most of them uses a ton of images and hard to skin or customize, or are very large in size.
Spectrum is a simple color picker jQuery plugin which is lightweight and offers a familiar interface. It is easy to skin and customize the plugin with CSS, and there are a wide range of modes and options to explore.