Growl, a system notification program for Mac OS X

Mac OS X Question: Is there a notification program for Mac OS X, like the notification balloons that appear on the task bar in Windows?

As of Mac OS X 10.5.7 there is nothing built into Mac OS X to provide this functionality, but there is a great, free application named Growl which provides similar functionality.

There are several cool things about Growl. First, it works with a number of Mac applications, including but not limited to Firefox, Easy Batch Photo, Komodo Edit, and NetNewsWire.

Second, it has a bunch of customization features available from the System Preferences dialog, including where to display it, how to display it, how long to display it, and more.

Growl System Preferences images

Here are a couple of images from the Growl System configuration panel in the Mac OS X System Preferences dialog. The first image shows some of the General Growl configuration options:

This next image shows the Growl Display Options in the System Preferences dialog: