The Help Markup Language team has released the specification for HelpML 0.2, an "XML-based file format and proposed standard for writing help documents" such as FAQs
and other topic-based information.
The spec looks pretty weak to me. I see no support for embedded HTML, no namespace, and no support for mixed content. There's no schema, DTD, stylesheets, or other tools that I could find; but version 0.3 is all Wikified so you should be able to fix this. :-)
ActiveState has posted the fifth alpha release of Komodo 4.0, a $295 payware
IDE for Perl, Ruby, PHP, Python, Tcl, and XSLT. Komodo runs on Mac OS X 10.3 and later, Linux, and Windows.
buldocs has released xnsdoc 1.2, a €49 payware "documentation generator for XML namespaces defined by W3C XML Schema in HTML in a JavaDoc like visualization. xnsdoc supports all common schema design practices like chameleon, russian doll, salami slice, venetian blind schemas or circular schema references. xnsdoc can be used from the command line, as an Apache Ant Task, as an Apache Maven Plugin, as an eclipse plugin or integrated as a custom tool in many XML development tools such as StylusStudio, oXygen XML or XMLWriter." Version 1.2 fixes bugs and adds some additional configuration options.
Syntext has posted the first release candidate of Serna 3.0. a $268 payware XSL-based WYSIWYG XML Document Editor for Mac OS X, Windows, and Unix. Features include on-the-fly XSL-driven XML rendering and transformation, on-the-fly XML Schema validation, XInclude, and spell checking. A roughly $500 enterprise edition adds a Python API and WebDAV support. Version 3.0 now allows text input in Chinese, Japanese, and Korean.
The Big Faceless Organization has released the Big Faceless Report Generator 1.1.32, a $1200 payware Java application for converting XML documents to PDF. Unlike most similar tools it appears to be based on HTML and CSS rather than XSL Formatting Objects. This is mostly a bug fix release. Java 1.2 or later is required.
Andrea Marchesini has released libnxml 0.13, a C library for parsing, writing, and creating XML 1.0 and 1.1. Version 0.13 adds support for proxies and SSL certification. libnxml is published under the LGPL.