Freemind
Van PropellorWiki
Any mindmapping tool can help you in organizing your thoughts or facilitating a meeting, but the advantage of Freemind is that it is free, since it is open source software
You can get it for free at this address http://freemind.sourceforge.net/wiki/index.php/Main_Page
And you can actually embed mindmaps in this Wiki thanks to the Mediawiki extension from freemind, just upload the mindmap as an image first and then refer to it using this syntax: <mm>[[Hello.mm]]</mm>
