You mean mind mapping, like with Freemind?
I have used freemind for my �berproject, and the program is really simple and usefull. However, i still can't really decide where to start. And the graphics part is really pulling me down. My problem is that i suck at graphics (not really suck, but i'm not as good as i would like to be) so I'm trying to make the engine without graphics and add the graphics when everything is finnished. This is really hard to do, since you can't really see your progress, and it feels like you're getting nowhere.