Good news for Flex developers!
The Data Visualization and Charting components which till now had only been available with professional versions of the Flex Builder are now open source, and can be used with the standard version of Flex Builder (or Flash Builder 4). Since the components are now open source they can inface also be used with 3rd party IDEs such as FlashBuilder (which is a free and open source IDE for Flash development).
The Data Visualization and Charting components for Flex are advanced ActionScript libraries which can be used for displaying complicated hierarchical data using the advanced data grid, or for rendering interactive dynamic charts using the charting components.
You can download the latest version of the Flex SDK (v3.5) and the charting components form the Adobe website.
The next version of of the Flex IDE (now called Flash Builder instead of Flex Builder) also seems to be nearing completion, and development of the open source Flex SDK has already moved on to Flex 4.1 (download a build from here).