As I understand it (also a newb
) Red Hat has deliberately disabled the MP3 support due to licensing concerns, a search of this site or google will turn up ways to enable MP3 support. I downloaded something like xmms-mp3***.rpm which was only 75kb and all was fine.
I found this site very
helpful when I first started using Linux (5 months ago), especially for installing software and then finding out where I installed it to lol (same configuration as you BTW)
Hope this helps