The RGBLED and mRGBLED controllers allow you to control the color of RGBLEDs. This might sound trivial, but it actually takes a lot of resources to let you be able to set an RGBLED to any color you’d like. In addition to just lighting an LED up with a given color, these boards also let you install a color or setup transition/animations effects. They are easily controller via an RS232 connection (serial port) or an SPI connection (logic level).
The boards can be built reasonably inexpensively and there are PC boards available for either model. All source code for the onboard PIC processor as well as the software for configuring and using the controllers is available. The protocol is a simple protocol well documented.
I’m currently studying timers and pwm control on AVR’s so i can build my own projects related to controlling RGB LED’s. I hope I’ll get something up soon.