GrowlTunesPlugin is a plugin for iTunes that allows you to painfully get Growl notifications from iTunes on track changes. You install the plugin into ~/Library/iTunes/iTunes Plug-ins and launch iTunes, it does have a rough preferences window that lets you configure the format of the notifications, configure a global hotkey to replay the track information and various other user requested settings. The preferences window is available under the View -> Visualizer -> Options menu item (when you have GrowlTunes as the selected visualizer). You don't have to have GrowlTunes as your selected visualizer at all times in order to work, the only reason to select it is to get access to the preferences window.