Set up mpd, continued
Start mpd when the system boots
Edit /etc/rc.local to include a section like this:
if [ "$1" = "" -o "$1" = "mpd" ]; then
if [ -x /usr/local/sbin/mpd -a \  
     -f /etc/mpd.conf ]; then
  echo -n ' mpd'; /usr/local/sbin/mpd
fi
fi
Note: The mpd section goes after:
 echo -n 'starting local daemons:'

 # Add your local startup actions here.
And before:
echo '.'


See http://erdelynet.com/tech/openbsd/rclocal-trick/ for more about my rc.local syntax.