Mindmapping tools online (free!)

Some free online mindmapping tools that you may wish to try out.

• Mindmeister: Can be used with its accompanying widget/browser extension Geistesblitz, so that you can submit ideas to Mindmeister immediately for mapping.
  
• Mindomo
  
• Bubbl.us:Cute, adorable, intuitive. Controls for changing bubble colours and adding nodes are located on each bubble - just mouse over.

However, as far as I can tell, they are not entirely suitable for non-linear storyboarding as you typically cannot connect two nodes to a new node, nor can be insert a new node in the middle of an existing chain. I could be wrong though.