ProgressBar.class.php is an easy to use solution for time consuming operations and loops in PHP.
The class increases the timelimit for script-execution (if safe-mode is turned off), prevents a browser-timeout by sending pieces auf the progressbar to the browser and gives the user live-feedback on the progress of the running operation.
As of version 1.2 you can use setter-methods to change the appeareance of the bar at runtime. Have a look at the source of this demo to see how it works!