Draw, create, print and fold beautiful 3D figures with Foldify
foldifyapp.com
foldifyapp.com
Also, I was a bit disappointed. When clicking it, I hoped for some tool that creates an origami design from a 3D model :-)
I was thinking of http://en.wikipedia.org/wiki/Mathematics_of_paper_folding. Examples and more math at http://static.usenix.org/event/usenix08/tech/slides/lang.pdf