Here's a website for everyone to take a quick look at (mainly the Mind Mapping section).
Some of the links lead you to free stuff (demos included). Some you'll have to dig into the ol' wallet to get.
If you ask me, stick to the free stuff for quickly plotting out the essentials. Most of us (I'm working on it...), have the Photoshop & Illustrator skills to jazz up the overall presentation later.
"Web 2.0 Backpack: Web Apps for Students" - [Scroll down to Mind Mapping]