I should start by saying that I can play mp3 files perfectly well in Juk.
I decided to give Amarok a try after reading a rave magazine review, but when I try to play anything from my music collection I get the message that "Xine cannot play mp3s". Am I missing a plug-in or something? BTW, Xine is the only engine showing in the selection window so I have no other choice.

you probably only have the gstreamer plugins installed. I think you need xine-ffmpeg and xine plugins. I suppose you have amarok-xine installed?

I recently installed FC7. Here is how I enabled MP3 support for Amarok using yum.

Login into shell as SU. Use this command rpm -Uvh http://rpm.livna.org/livna-release-7.rpm.
This will tell yum to where to locate packages.

As SU enter yum install amarok-extras-nonfree. You will need to answer a series of questions. Let the OS do its job, log out and log in again. This will allow for a number of formats including MP3.

It has been years since I have used SUSE. These commands might vary slightly. If livna is FC (and variants) specific, try using freshrpms in place of livna.

This maybe worthless to SUSE users but should work for FC, Mandriva and Ubutu(?)users.