A comment in an Article on Debian Administration on desktop notifications mentioned a useful command for the "song change" plugin in xmms:
kdialog --title "Playing on xmms" --passivepopup "` xmms-shell -e status |grep Playing |cut -d":" -f2`" 5
As kdialog is quite slow (takes 400 ms for connecting to dcop, etc.) and displays a very ugly balloon popup (like in MS Windows) I prefer
notify-send -u low --icon=/usr/share/icons/crystalsvg/32x32/apps/xmms.png "Playing on xmms" "`xmms-shell -e status | grep Playing | cut -d':' -f2`"
Very slick, indeed:
notify-send is in the libnotify-bin package in Debian.