What's your mp3 player?
Hey, if I want to help you, I have to find out what program you are using... and what distro.
Because, if you didn't know yet, redhat does not include an mp3 codec with it's distribution, due to some copyright problems. BUT, you can still find it, all you have to do is install the right package.
If you are using some other software than Redhat an xmms, well, explain, and I'll see what I can do for you...