This is the code I use for my Cheerlights display. You can see the display itself on Flickr at: http://www.flickr.com/photos/8190411@N07/sets/72157628410760271/

Last year, I used the (wired) Ethernet Shield on the Arduino and just plugged the tree directly into my home network. I was unable to get all the bugs out of that code and also desired to have the tree be more portable. This year, I started off by finding some Python code to grab the color. Then I used XBee modules to link the Arduino to my Mac and wrote some serial code to let the tree request the color and have the Mac fetch it from the internet and send it to the tree. Wanting even more portability and less power use, I reworked the Python script to run on my new Raspberry Pi. The Pi has a wifi dongle it uses to get an internet connection. Now the Pi is the color server and both it and the tree display can be run from battery packs.