When I try to run Amarok in Fedora 6 I get this error message: xine was unable to initialize any audio drivers.
When I run as root, I have no problems and everything works fine.  I can't get audio from anywhere else (vlc, kmix, xine

Please see
man addgroup
or
man group (which tells you the format of /etc/group)

It seem you indeed have to add yourself to the appropriate group (which might be audio, you can verify this by checking the group name which owns the files in /dev/snd/)