Our website provides a free download of FxStyleExplorer 3.0. The software lies within Development Tools, more precisely IDE. The actual developer of the free program is RiaFxZone.
From the developer:
The Adobe Flex3 Style Explorer provides a visual way for you to see how changing style settings of Flex 3 user interface components will affect the display of your application. This specific application is broken up into three sections: Style Controls, Sandbox, and CSS. These sections allow you to respectively test, view, and learn the style settings that are required to achieve the “look” that you have in mind.
You may want to check out more software, such as GnuWin32: LibIconv, FrameDemo2 or TextSamplerDemo, which might be similar to FxStyleExplorer.