A Flash based demonstration of Argumentative and some of its editing features is available from the project home page.
The movie was created using Wink - http://www.debugmode.com/wink/
Argumentative is open source Argument Mapping software. It allows you to view and manipulate the structure of an argument in terms of a main premise and a hierarchy of reasons and objections.
For more information visit the home page at http://argumentative.sourceforge.net/