If you find yourself doing a lot of work with Flex, the Flex Language Reference will be your new best friend. Even as your skills and knowledge increases, you’ll keep coming back to this ultimate guide for Flex and Flash Player’s APIs. Every component property, method, event, and style is at your fingertips, often with useful inline examples. You can access it directly under Flex Builder’s Help menu too, if you prefer.
The flexcoders mailing list is a great place to ask questions if you’re having some particularly difficult problems with Flex. You can also read theflexcoders archives through The Mail Archive for an easier reading and searching experience. Also consider subscribing to the flexcomponents mailing list to learn about building custom components for Flex. You shouldn’t post general Flex questions here because this list is specifically designed for discussion focused on components. Even if you aren’t into building components, I recommend watching the discussions there because many of the list’s experts share useful insights into many hidden aspects of the Flex framework.