Dmitri Popov at Linux.com - Create impressive charts with Open Flash Chart:

"Creating a high-quality chart for the Web can be a challenging task, but open source software like Open Flash Chart (OFC) makes it a cinch. As you might guess from its name, the core engine of OFC is written in Adobe Flash. Although this means that users need a Flash browser plugin to view charts created with OFC, this approach has a significant advantage: it allows you to produce professional-quality graphs with minimum effort, because the core engine does all the heavy lifting, and all you need to do is to specify configuration options for your chart and feed data into it."