After seeing what other people have done with their media indexers I thought it would be a good idea to collect all the sources of icons in a single thread. I've found various forum posts and here's what I've located so far.
If you have other sources please share the links. I've found these most useful for what I've setup:
I've found 256x256 .PNG has the best looking output on Zappiti, 128x128 gets stretched and looks poor.