Xmind - Xmind is a brainstorming and mind mapping application.

FlowMapp - FlowMapp is a UX planning tool for creating visual sitemaps and user flow.

MindManager - With MindManager, flexible mind maps promote freeform thinking and quick organization of ideas, so creativity and productivity can live in harmony.

Octopus.do - Build your website structure in real-time and rapidly share it to collaborate with your team or clients. Start prototyping websites or apps instantly.

MindMeister - Create, share and collaboratively work on mind maps with MindMeister, the leading online mind mapping software. Includes apps for iPhone, iPad and Android.

DYNO Mapper - Create Sitemaps with the DYNO Mapper Visual Sitemap Generator.