Mary Chipman of MCW Technologies has published an interesting article on MSDN, covering XML authoring in Office 2003 tools. Mary provides a beginner's walkthrough of new functionality for using XML, allowing you to separate the data in a document or worksheet from its presentation in Word 2003 and Excel 2003. You can then use and modify the content with other tools and exchange data with other XML systems.
The article explains how to use standard Office 2003 tools to perform a number of day-to-day tasks. These include how to:
-- edit pre-existing XML files
-- set a specific transform (XSLT) rule set for a given XML data file
-- import XML data
-- protect XML tags when editing in Word
For those just getting their feet wet with Microsoft's XML capabilities, this is a comfortable first step.
Read the MSDN article