I’m a big fan of ASDoc! I use it to document all of my major library releases (ex. GTween, SPL, Wander, etc).
ASDoc allows you to write simple comments in your AS3 classes, then generate HTML documentation from them. This is great in that it allows developers to maintain source code and documentation simultaneously, and it reduces the overall burden in writing documentation by reading the core API information from the code directly. Unfortunately, the ASDoc tool is command line based, and can be a bit of a pain to work with. There are ant integration tools available, but they don’t suit every need or scenario.
That’s where ASDocr comes in. Building on the new nativeProcess APIs in AIR 2.0, it provides a simple graphical interface to ASDoc. It walks you through all of the common params ASDoc supports, with help for each of them. You can save configurations for multiple projects, and clone configurations to act as a starting point for new projects.
It only takes a couple of minutes to set up a basic configuration (only 2 settings required) and start generating documentation. ASDocr will display the output from the ASDoc executable, and notify you if an error occurs. You can even use CMD/CTRL-ENTER as a shortcut to run (muscle memory FTW!).
Here are a couple of screen shots showing it in action:

