Xmind - Xmind is a brainstorming and mind mapping application.
FreeMind - FreeMind is a premier free mind-mapping software written in Java.
MindMeister - Create, share and collaboratively work on mind maps with MindMeister, the leading online mind mapping software. Includes apps for iPhone, iPad and Android.
Mindomo - Easy-to-create and share mind maps, concept maps, task maps and outlines. Mind mapping software for Web, Desktop, iOS and Android. Mind map with us for free!
MindManager - With MindManager, flexible mind maps promote freeform thinking and quick organization of ideas, so creativity and productivity can live in harmony.
TheBrain - TheBrain: The Ultimate Digital Memory