Java Toaster is a java utility class for your swing applications that shows an animated box rising from the bottom of your screen with a notification message and/or an associated image (like msn online/offline notifications).
This is a simple screenshot:
Java Toaster is platform independent and it is easy to integrate and use in your swing applications.
You can also customize the layout changing fonts, colors and images.
Last but not least is completelly free and opensource!
Go to sourceforge homepage