VocDoc is a little Ruby script which produces documentation for OWL/RDFS ontologies and vocabularies. There are options to produce either an HTML page to put as documentation online (in a style very similar to the FOAF specification), or LaTeX code to include in larger LaTeX documents, such as project deliverables or technical reports.
Here are some screenshots to give you an idea of what the HTML output of VocDoc looks like. All are excerpts from a Web page created for the Semantic Web Conference vocabulary (SWC), which was generated directly from the vocabulary source file.
An example of the documentation for an individual class generated by VocDoc. Formal definitions such as super- and sub-classes, union-of, intersection-of, etc. are given. In addition, human-readable documentation is included, which can consist of arbitrary HTML code. At the bottom, each term definition includes a link to a SW index showing usage of this term.
The documentation for VocDoc is included in the source code. You can also look at it online.