You can pan and tilt by holding the mouse button down on the picture and dragging. You can look around you, and up and down. To zoom out, press the < key. To zoom in, use the > key. The zoom is limited to a reasonable range.
If you see no picture, make sure that your browser has Java turned on. In Netscape, go to Edit | Preferences... | Advanced and check the option 'Enable Java'. In Explorer, go to Tools | Internet Options, select the security tab and click on custom. Scroll down to the Java section and select 'High Safety'. Go back to the page you were viewing and click the reload button.
You should see the status screen first:

Sample of the status screen, there is no panorama here.
The red bar shows the progress of down-loading the panorama by turning green. Each panorama on this site is approximately 100 kB in size and takes about 15 seconds to download over a phone line. After a brief decompression, the panorama is shown. If the green bar persists, try clicking or dragging on the picture.
After viewing several panoramas, Netscape sometimes displayes an 'Out of memory' error in the status line. Exit the browser and restart it.