MindNode is a powerful and intuitive mind mapping application. Its focus and flexibility make it the perfect tool for brainstorming and organizing your life - and iCloud sharing means you always have your mind maps with you. MindNode lets you lay out your notes and tasks visually so you can get a bird's-eye view of your project. The clutter-free interface lets you concentrate on generating and connecting ideas, and an infinitely expanding canvas means that no matter how big or complicated your project gets, MindNode can keep up.
Note: While the software is classified as free, it offers in-App Purchases.