If you are making an extension for Joomla version 2.5 or above, Joomla has a built-in colorpicker field type. You are recommended to use that rather than this tool.
This product is is free of charge, if you would like to download it you can pay with a Tweet or a Facebook like, just click the button below.
The color picker is compatible with Joomla 1.5 and 2.5, with mootols 1.1, 1.2 and 1.3, and does not require any other javascript library, so no conflicts with the Joomla admininstrator template. It is very lightweight, consisting of a single javascript file, plus the the Joomla element and formfield classes necessary to generate the custom parameter.
The color picker modifies a standard Joomla parameter text field to generate a color picker. It returns a six-digit hexadecimal color code. It decays gracefully - if for any reason the script does not function then the user will see a standard text field. However is has been tested in Internet Explorer 7 and 8, plus Firefox, Google Chrome, Opera and Safari, and should work in any standards compliant browser.