Oh goodness, another very poorly maintained article on how to do something using Gentoo... I wish I had infinite time to improve the Gentoo Wiki..
I'm trying to write the blinkin light program for this Arduino that I have here and software issues on the PC are causing me headaches....
Gentoo Wiki -Arduino
I think I can improve this one, I'll give it a shot.
UPDATE: I didn't improve that wiki article, and I think it's unlikely that I'll go back and work on it. But that just means you can! ... If you want to. :-)