PHP/SWF Charts is a slick PHP package for dynamically generating charts as Flash files. The results are good looking and full-featured. I especially liked the idea that everything is defaultable. As the tutorial shows, this code:
//include charts.php in your script
//draw a chart using the default values
will draw a bar chart with bogus defaulted data. Of course, the resulting chart is useless, but it makes it extremely easy to get off the ground with the package.