Availability Calendar Color Picker

Hi, the users of my website [login to view URL] should have the opportunity to pick their own individual colors for the availability calendars they create. Please check the website and register to see how the calendar works. Attached you will find a picture of the edit page of an availability calendar and you get an idea of how it should look like later. When clicking on edit of "Fully booked, Reserved and Available" a color mixer (eg [login to view URL]) should appear in a lightbox (eg [login to view URL]) and the user can pick a color, apply or reset it. When applying the color, the color should change directly on the edit page in the calendar, when clicking on saving the color is stored in a simple Drupal CCK field and recalled through a PHP snippet in the template file of the Drupal theme. Please check if you are really aware of the issue before you bid on the project. If there are any questions please ask before.