Mind maps have become very popular over the past decade for a reason: visualizing information helps you remember things better and understand the relations between ideas better. Applications from this category are the tools you need to design mind maps suited to your specific needs.
Blue Crystal Software Corporation
Hands High Software, Inc.
Volker Boerchers, Dimitry Polivaev
Art Plus Marketing & Publishing
PRIMASOFT PC, INC.
The Golden Section Labs.
Lazy Bayou Software