AxKit is a suite of tools for the Apache httpd server running mod_perl. It provides developers with extremely flexible options for delivering XML to all kinds of browsers, from hand-held systems to Braille readers to ordinary browsers. All this can be achieved using nothing but W3C standards, although the plug-in architecture provides the hooks for developers to write their own stylesheet systems, should they so desire. Two non-W3C stylesheet systems are included as examples.
The toolkit provides intelligent caching, which ensures that if any parameters in the display of the XML file change, the cache is overwritten. The toolkit also provides hooks for DOM-based stylesheets to cascade. This allows (for example) the initial stylesheet to provide menu items and a table of contents, while the final stylesheet formats the finished file to the desired look. It's also possible to provide multiple language support this way.
AxKit and its documentation are available from http://www.axkit.org/.