Well, I just read about this in LFY today and wanted to try it. Seems like its a cool tool. I made a introductory Linux presentation (meant for our Java developers) in this. May be it is not a real strong use case. But, Freemind sure did help me organize things a bit. The software has got some nice folding and re-arranging options which I liked.
You can find FreeMind at http://freemind.sourceforge.net/wiki/index.php/Main_Page
I am also uploading the stuff that I made (exported to jpeg) using this.