See the iTunes Track in the Dock

By Richard Mallion

Here’s a great little tweak for the Dock that will cause a pop-up window to momentarily appear each time iTunes begins playing a new track
Quit iTunes if it’s open, then open a Terminal window and type the following:

defaults write itunes-notifications -bool TRUE;killall Dock

Then start iTunes and try playing a track. The pop-up fades away after a few seconds.
To add the iTunes icon to the pop-up window, type the following into a Terminal window:

defaults write notification-always-show-image -bool TRUE; killall Dock

To deactivate the pop-up at a later date, quit iTunes again, then open a Terminal window and type the following two lines:

defaults delete itunes-notifications
defaults delete notification-always-show-image;killall Dock