Migrating HTML to DITA, Part 1: Simple Steps to Move from HTML to DITA
http://www.ibm.com/developerworks/xml/library/x-dita8a/?S_TACT=105AGY82&S_CMP=GENSITE

Anderson, Robert, Don Day and Erik Hennum
IBM
2005

Abstract:

The Darwin Information Typing Architecture (DITA) has emerged as a standard topic-oriented document architecture. DITA holds many advantages over information authored directly in HTML, including better reuse, easily changed presentation styles, and easy single sourcing. This article, the first of two parts, explains how to get a quick start with DITA using HTML topics that are already available. It shows you how to use the provided XSLT transform to do the migration, and examines what is needed to ensure quality results.