StoryboardThat:
"A storyboard is a graphic organizer that plans a narrative. Storyboards are a powerful way to visually present information; the linear direction of the cells is perfect for storytelling, explaining a process, and showing the passage of time. At their core, storyboards are a set of sequential drawings to tell a story. By breaking a story into linear, bite-sized chunks, it allows the author to focus on each cell separately, without distraction." - Aaron Sherman
Link to StoryboardThat Website