The Adobe Consulting Team has posted a Flex 2 version of their Flex Style explorer.
This is an application that allows you to visually tweak the styles of the Flex components, and then get the resulting CSS to use in your application.
I just finished up working on a highly stylized application with Flex 2. While CSS / Styling support is very good in Flex 2, it can be difficult to figure out just what style does what you need. This application helps solve that problem.
You can view the application, as well as read more about styling in Flex 2 here.