The source code can be downloaded from http://www.22ndcenturyofficial.com/ForBlogDoNotDelete/ColorPickerView.mxml
(right-click on PC, Control-click on OS X and select "Save Target as..." or something like that). PS - this is my band's official web site so while you're there take a listen to our music!
The controllers are simple Spark Horizontal Sliders that have ranges from 0-255. Each slider has a change event handler registered to the same function.
The logic is included to lay these out for both portrait and landscape modes. A visual reference to the current color is represented within a Spark rect. The Button calls a blank function to be used to take whatever action you want to set a color.
A small utility class is used to prevent incorrect values from being written when ranges are less than one character long. The checkLength() function has comments and is self explanatory. This is to prevent '0f0f0f' from returning "fff" if the values are all 15.