Musicality can optionally use Growl, a notification service, to display information about each new song that plays. If you've had your Mac for any length of time there's a good chance it is already installed. If not, you can learn more at the Growl website.

A Musicality growl.

Growl comes with a number of display styles; my favorite (shown here) is Smoke. You can configure Growl from System Preferences.