I just updated my neorainbowduino firmware package. It contains firmware for rainbowduino and arduino.
Now here comes the sexy part: I also released a processing library (incl. two examples) - so you can send frames to your rainbowduinos from processing!
I published more information at my blog: http://www.neophob.com/2010/09/neorainbowduino-processing-library/
hope you like it, cheers!