My Playstation2 Linux kit is in and installed. I got it setup last Wednesday, including transfering a few mp3s to it and getting mpg123 to compile. That took a small amount of effort on my part, as there wasn't a Linux PS2 target available for mpg123 to use directly.
I haven't gotten the USB -> Serial DB9 adapter yet to hook the Light Chaser up to it. But, I have been doing some research into the special vector processors that are within the PS2 to attempt to free up some of the regular CPU time within the PS2 by giving them some of the mp3 decoding work to do. I think that I'll end up passing off some mp3 decoding floating point work to the first processor (VU0). Once I have that working, then I'll look into tossing some special graphical stuff onto the second processor (VU1) because it's directly tied to the graphics chip (GS).