You can use html in tooltips, which means you can add images, which means you can add animated gifs. Of course, I've never tried this so I don't know if animated gifs will work.
If you want something more complex than that, you're going to have to customize JToolTip or build your own tooltip facility.
http://www.codeguru.com/java/articles/122.shtml
Message was edited by:
Jaspre