Cheerlights running with an Arduino + Arduino Ethernet Shield + Shiftbrite.

Required:

Arduino 1.0 IDE
Arduino Duemilanove with ATmega328 or Arduino Uno. Must have the ATmega328 due to Flash and RAM.
Arduino Ethernet Shield
ShiftBrite


Important constants:

numberSB is the number of ShiftBrites on the chain.
datapin = DI on the ShiftBrite
latchpin = LI on the ShiftBrite
enablepin = EI on the ShiftBrite
clockpin = CI on the ShiftBrite
redlevel, greenlevel, bluelevel is for setting the output level for each channel on the ShiftBrite

stepdivisor is what to divide the number of steps by to adjust the fade
stepdelay is how much of a delay between steps on the fade
thingSpeakInterval is how often in ms to contact Thing Speak to get the current color



One note, if you say there's less ShiftBrites on the chain than there really is, it'll look strange. Also, I have not tested it with more than 2 ShiftBrites, but I should.