Storyboard That is an online web application that allows you to easily create expressive storyboards easily. It features hundreds of scene backgrounds, characters, and props. If they don’t have something you need, you can upload your own images.
Each scene element can be dragged into the scene, and when it’s dropped, has a usable default size and position. If an element needs to be customized, the user interface offers various options upon dropping the element into the scene, or when selected. Characters may be posed, scenes can be set to daytime or nighttime lighting, and even the color of the toothbrushes can be changed. The interface seems to strike a very good balance between offering many features and not requiring the user to tweak absolutely everything that goes into the scene.
Storyboards can be exported as a single image, sets of images in a zip file, and PDF or Powerpoint Presentations. It can also be played as a slide show right off the website.
Personally, I agonize too much over how bad my drawing skills are, especially when trying to make something fast. This tool seems to allow me the ability to make drawings very quickly, and still look rather good.