If you followed the previous tutorial on triple booting your eeePC, you probably have noticed that your OS X install does not have any sound. One work around is to buy an external USB audio card. I bought the cheapest one I could find (SYBA SD-CM-UAUD USB). However, I find in inconvinient to carry around the USB dongle. I had it in the case which came with the EEE, but it scratched my EEE.
After some research, I found a tutorial on how to enable the sound to work. I followed it and it enabled me to listen to music on my EEE without the external audio card. You can find the tutorial at IPIS-OSX.wikidot.com. I have created a zip which includes all of the necessary files in order to have you EEE happily singing through its internal speakers. Download the archive from here.
If you run into any problems, please post a comment here or on the IPIS-OSX site.