"Conceptual Maps are simple and practical knowledge representation tools that allow you to convey complex conceptual messages in a clear, understandable way. They facilitate both teaching and learning." http://www.infovis.net/E-zine/2004/num_141.htm See map http://www.infovis.net/images/CmapTools.gif
Download Cmap tools http://cmap.ihmc.us/download/
There’s also a free, web based, similar tool in Spanish created in the Universitat Pompeu Fabra of Barcelona, Spain, by Cristòfol Rovira that automatically generates the necessary code to include the map in XML format using the Topic Maps standard... http://www.mapasconceptuales.com/

The Institute for the Interdisciplinary Study of Human & Machine Cognition (IHMC) was established in 1990 as an interdisciplinary research unit of the University of West Florida. Since that time, IHMC has grown into one of the nation's premier research institutes with more than 115 researchers and staff investigating a broad range of topics related to understanding cognition in both humans and machines with a particular emphasis on building computational tools to leverage and amplify human cognitive and perceptual capacities. http://www.ihmc.us/about.php

See drop-down icons (on-click) used throughout the map http://cmap.ihmc.us/ often leading to other maps.

CMC 2004 - First International Conference on Concept Mapping ; Pamplona Iruña, Navarra, Spain - September 14-17, 2004 Honorary Chair: Joseph Novak, Cornell University and Institute for Human & Machine Cognition http://cmc.ihmc.us/Index.htm

Pictoral County Maps http://www.quincetreepress.co.uk/

http://www.1-900-870-6235.com/eLearning/DWFrameset-1.htm