DITA Publications
Books

Introduction to DITA, by Jennifer Linton and Kylene Bruski (Comtech Services), 2006).

DITA Pocket Guide, by SiberLogic, 2006.

DITA Open Toolkit User Guide 1.3.1 (PDF),
HTML Frameset version
by Anna van Raaphorst and Richard H. (Dick) Johnson,
VR Communications, 2006.

Developing Quality Technological Information: A Handbook for Writers and Editors (2nd Edition) , by Gretchen Hargis, Michelle Carey, Ann Kilty Hernandez, Polly Hughes, Deirdre Longo, Shannon Rouiller, Elizabeth Wilde (IBM Press, Information Management Series, 2004).

Information Development: Managing Your Documentation Projects, Portfolio, and People, by JoAnn Hackos (Wiley, 2006).

XML and Framemaker, by Kay Ethier (Apress, 2004).

Articles
An XML Architecture for Technical Documentation: The Darwin Information Typing Architecture By Don Day, Erik Hennum, John Hunt, Michael Priestley, David Schell, Nancy Harrison
Wikipedia on DITA.
OASIS Roadmap for DITA development
DITA - Getting Started by Christian Kravogel and Boris Horner
Going DITA by Constantine Hondros
To DITA or not to DITA? - Palimpsest, Friday, January 06, 2006
DITA for DocBook - Implementing the Darwin Information Typing Architecture for DocBook.
Lovely DITA, Meta Maid, Ready-made Metadata by Bob Doyle (EContent Magazine)
DITA - The mechanics of a single sourcing project by France Baril
Planning for DITA Success - Part One: How to Set Up the Right Team and the Right Strategy (PDF) by the Rockley Group
Planning for DITA Success - Part Two: How to Deploy DITA, Step-By-Step (PDF) by the Rockley Group
DocZone is doing it with DITA by the Rockley Group
DITA - What you need to know (PDF) by the Rockley Group
The Darwin Information Typing Architecture: Avoiding Proprietary Lock-in - by Kay Ethier and Scott Abel
Adobe Systems Speaks Out on DITA: Internal use of FrameMaker, CMS, and DITA - by Kay Ethier and Scott Abel
DITA at The Content Wrangler by Scott Abel
Subsetting and customizing DITA by Bernard Aschwanden
To DITA or not to DITA? by Scriptorium Palimpsest
FrameMaker 7.2 and DITA by Bill Trippe
More DITA: Another Interesting Case Study by Bill Trippe
DITA and the Beatles by Bill Trippe
Topic-Oriented Information Development and Its Role in Globalization by Bill Trippe
DITA for DocBook by Norm Walsh
What Managers Need to Know About DITA
DITA Open Toolkit Bug Tracker
Getting Started with DITA (Bob Doyle Blog)
Anne Gentle DITA Blog

Articles at IBM developerWorks

Introduction to the Darwin Information Typing Architecture
Why use DITA to produce HTML deliverables?
Migrating HTML to DITA, Part 1: Simple steps to move from HTML to DITA
Migrating HTML to DITA, Part 2: Extend the migration for more robust results
Implement a DITA publishing solution without abandoning your current publishing system investments
Specializing topic types in DITA
Specializing domains in DITA
Design patterns for information architecture with DITA map domains
Subject classification with DITA and SKOS
An XML-based information architecture for learning content, Part 1: A DITA specialization design
An XML-based information architecture for learning content, Part 2: A DITA content pilot
Transform Eclipse navigation files to DITA navigation files
 
Search DITA references at IBM developerWorks (81)

Online Tutorials and Workshops

Michael Priestley, Introduction to DITA, and Best practices for authoring topics
Michael Priestley, Task-oriented information architecture using DITA maps
Michael Priestley, Introduction to specialization, and simple demonstration
Michael Priestley, Full specialization demonstration
W.Eliot Kimber's Specialization Tutorial