Xmind - Xmind is a brainstorming and mind mapping application.
OpenideaL - Get OpenideaL's open source idea management platform, collecting insights from employees & customers, with DevOps support from HOSSTED.
MindMeister - Create, share and collaboratively work on mind maps with MindMeister, the leading online mind mapping software. Includes apps for iPhone, iPad and Android.
Idea Drop - Set team challenges to capture the very best business ideas
FeatureMap - FeatureMap story mapping, simple and effective realtime collaboration and collective intelligence tool.
Aha! Ideas - Idea management software to drive innovation. Crowdsource feedback, engage your community, and analyze trends — so you can prioritize the best ideas.