Powerclients is a new german blog specialiced on the development of RIAs with Flash and Flex. As a free download they offer a ColorFan component which uses the interface metaphor of a Pantone fan. It's very nicely done and feels good to interact with. I personally wouldn't have chosen the 216 web color palette as a default - as that's probably the most uninspiring color palette known to mankind. But of course the component allows to change that and define your own colorset.