This WebZoomer tour of the NYU CAT and related Sites is an example of zooming in a Java Applet without the use of any Plug-Ins. I suggest you expand your Web Browser to full-screen, to get the nicest effect. Then try clicking on things.
If you want to make a zooming SiteTour of your own, follow the instructions here.
We haven't yet released the underlying Java implementation for this, but this demo should give you a small flavor of how you might build componentware for a zooming client. - Ken Perlin, 1998