shell_exec("/usr/bin/mp3 play /tune.mp3")
is tune.mp3 really in the root directroy or is the file within the directory
structure of your web site? If you call 'shell_exec' you are running a
seperate linux process. If your file 'tune.mp3' is actually in
/var/www/mywebsite/tune.mp3 then you need to put the full path in.
Jon