From Photoshop actions to Photoshop scripting?

Question

I would like Photoshop to automatically execute the following task for a given folder:

1. Load all PNG files in a given folder.
2. Convert each file\'s mode to

Answer 1

To update Kevin's answer, ScriptListener is now hidden in a different place:

http://www.adobe.com/devnet/photoshop/scripting.html

inside "Scripting Listener Plug-in". The plugin directory in Windows has also changed, typically:

C:\Program Files\Common Files\Adobe\Plug-Ins\CC