The following websites and lists are excellent starting places for information about DocBook and XML:
The most recent online version of this book can be found at http://docbook.org/.
OASIS maintains two public DocBook mailing lists:
This list is for general questions, comments, and discussion about DocBook, including questions about the schemas, syntax, semantics, and markup.
An archive is maintained at: http://lists.oasis-open.org/archives/docbook/.
This list is for questions, comments, and discussion about implementing DocBook, including questions about formatting, processing, using the stylesheets, and editing.
An archive is maintained at: http://lists.oasis-open.org/archives/docbook-apps/.
You can subscribe to either list at: http://www.oasis-open.org/mlmanage/.
The DocBook stylesheets are a set of stylesheets for use with an XSLT engine like xsltproc or Saxon. The stylesheets can transform DocBook XML documents (including documents using DocBook 5.0 and earlier versions) into output formats like HTML, PDF, various help formats, and the ePub ebook format. The stylesheets are open source software maintained by the DocBook community.
The DocBook Wiki contains a wide variety of DocBook information, from FAQs to lists of consultants.
A large list of XML resources: http://xml.coverpages.org ...