I know this isn’t 3D Origami related but I just found a really cool FREE online program that’s almost like Photoshop. It’s call Pixlr and you can use it at http://pixlr.com/editor/. Also a cool site to make a diagram would be Gliffy just go to http://www.gliffy.com. Gliffy kinda sucks because you have to sign up for a free account to use it. But Pixlr is absolutely FREE, no strings attached. Have Fun!