I have been mind-mapping for years and years using some of the earliest software applications back in the 1990s. I love sharing the power of mind mapping, at least how its aligns for me with my personal productivity process and system for agile productivity.
Find out about the basics here: Wkipedia: Mind Map
Find a list of Software Applications here: Wikipedia: List of Concept and Mind-Mapping Software
One of my favorites is The Brain because of its dynamic feature to reorganize around the element you are centralizing your attention on, making it the central node of the mind-map … although it can get a little over-whelming if you aren’t careful.