Modular (3D) and regular origami diagrams. The site isn't in English, but the imágenes are sufficient for advanced origami folders. Definitely check out the molecules and cubes.
Amazing modular origami, where tu basically fold a "piece" multiple times, then put all the pieces together to create an awesomely complex-looking 3D origami module.
A good site with lots of pictures and enlaces to many other sites, including "phone diagrams" (text-only descriptions that tu could read/hear on the telephone).