What users say:
“Cheers for a great tool that actually makes programmers want to write documentation!”
Sphinx is a tool that makes it easy to create intelligent and beautiful documentation, written by Georg Brandl and licensed under the BSD license.
It was originally created for the new Python documentation, and it has excellent facilities for the documentation of Python projects, but C/C++ is already supported as well, and it is planned to add special support for other languages as well. Of course, this site is also created from reStructuredText sources using Sphinx! The following features should be highlighted:
Links to documentation generated with Sphinx can be found on the Projects using Sphinx page.
For examples of how Sphinx source files look, use the “Show source” links on all pages of the documentation apart from this welcome page.
You may also be interested in the very nice tutorial on how to create a customized documentation using Sphinx written by the matplotlib developers.
There is a Japanese translation of this documentation, thanks to the Japanese Sphinx user group.
A Japanese book about Sphinx has been published by O'Reilly: Sphinxをはじめよう / Learning Sphinx.