It looks like Conor already has all of these resources listed, but I wanted to add a discussion with the list as well:
DB2 pureXML technology (Product Web site)
This is the main DB2 product Web site for pureXML.
Information Management and XML technology developerWorks domain (IBM community Web site)
This is the main developerWorks Web site from which you can access articles, online tutorials, and other technical resources about DB2 and XML standards and technologies.
IBM DB2 9 pureXML Guide (IBM Redbooks, html and pdf)
This IBM Redbooks publication describes the pureXML data store, hybrid database design, and administration. It explains what XML schemas are, how to use industry standards to implement them, and how to manage XML schemas. It covers how to use SQL/XML, XQuery, and XPath for querying XML data by providing easy-to-understand examples and how to use XML technology efficiently in business applications.
Get started with XPath (Tutorial)
This tutorial introduces the W3C standard XPath Version 1.0. This tutorial is intended for people who do not know XPath or who want a refresher. If you plan to use XSLT, you should take this tutorial first. You will learn what XPath is, what the syntax and semantics of the XPath language are, how to use XPath location paths, how to use XPath expressions, how to use XPath functions, and how XPath relates to XSLT.
DB2 9: pureXML Overview and Fast Start by
Cynthia Saracco,
Don Chamberlin,
Rav Ahuja (IBM Redbooks, html and pdf)
This IBM Redbooks publication provides a concise introduction to pureXML, with short, precise examples and explanations that provide a distilled version of the knowledge essential to start working with pureXML. This book is a compilation of many of the IBM published articles on pureXML.
Native XML support in DB2 (White paper, pdf)
This white paper provides a technical overview of XML support in DB2 products. It explains how XML data has been stored in relational database systems in the past using data type mappings and explains the limitations of these approaches. It then introduces the concept of pureXML and what it means for XML data to be stored natively within a database. It explains the benefits of this approach and how this implementation can be complemented with features such as XML indexes, a full XQuery language, SQL/XML, XML schema support, and utilities that support the bulk loading of XML data.
pureXML in DB2 9: Which way to query your XML data? (Article)
This intermediate-level article discusses DB2 pureXML support and compares the two methods by which you can query XML data in a DB2 database: SQL/XML and XQuery. By providing examples, this article explains the relationship between these two query access language syntaxes, the circumstances in which each method is preferred, the benefits of using each independently, and the use of them together to perform more complex queries.
pureXML wiki (Wiki)
This Web site contains links to numerous articles, demos, webcasts, and other information about DB2 pureXML published by IBM and other parties
Alphaworks DB2 pureXML download and demo site (Download)
This Web site contains industry-specific DB2 pureXML software offerings and resources.
DeveloperWorks DB2 pureXML forum (Forum)
This DeveloperWorks forum is one of the fastest ways to get any pureXML questions answered.