Thanks for the info trueblue. I just installed mpg123 and it sounds great. It is actually using less than 2-7% CPU for me. (1ghz tibook)
This might come in handy when I'm trying to preserve battery power. However, I tested iTunes 3 with the same mp3 files and it's utilization is about the same, roughly 7-9%. Strangely, iTunes will spike to 15% every 5 or 6 seconds, but generally it's low. Probably due to my CPU.
Seems like for those with slower CPUs mpg123 can help out a lot.
Search for 'mpg123' on versiontracker.com in the OSX section and you will find a number of wrappers for it. I recommend Mu; it seems to be the best one...but it does not have nearly as many options as simply using the command line.
