MOOD-DIMMING Power Scheme for RGB LED; changing color depending on amplitude

Is there anyone with know-how to setup a scheme for a test, to get a RGB LED giving different colors on different amplitudes. So when dimming it changes color fluently.

Should be programmable, only I don't know how.

Can anyone help me out?

Cheers, Paul

Have you looked at this? http://www.arduino.cc/en/Tutorial/Fading