1. Requirements

 Documentation Summary

 Page Summary

You need at least the following four free development tools:

1. Java 5+ (6+ working): Download Sun JDK and install it.
2. Eclipse 3.2+: Download Eclipse 3.2+ and unzip it somewhere (NOTE: It is always a good idea to avoid paths with whitespace). You may, of course, use another IDE, but you will not be able to use Eclipse specific plugins and sample projects.
3. Flex 2+ SDK: Download Flex 2+ SDK and unzip it somewhere (NOTE: idem), say /flex_2_sdk.
4. Flex 2+ Ant Tasks: Download Flex 2 Ant Tasks, unzip it and copy lib/flexTasks.jar to /flex_2_sdk/lib (adapt the path if you did not install Flex 2 SDK in /flex_2_sdk). This tool is already included in Flex 3 SDK so you do not need to download it if you use Flex 3.

You may also read and follow the recommendations in this excellent article in order to customize your development environment.