A few years ago I began playing around with software-based mind map applications but never really found them all that useful. Perhaps there was nothing complex in my life that needed "mapping" at that time; life, in the past, is always simpler.
I think most people mind map instinctively one way or another, and after recently revisiting the software-based concept with Freemind, an open-source mind mapping Java application, the reasons to use it are much clearer (as are my thought processes for various ideas and projects).
Check it out. I think you'll find it very intuitive as well as an excellent tool to break down complex ideas into much more manageable parts.