Check out the Multidomain MDM section on Initiate's blog, Mastering Data Management, for Marty Moseley's superb 9 part series that takes you from the basics of multidomain to building a business case.
Information Management: Multidomain MDM for Business Success
Information Management: Choosing the Optimal Multidomain MDM Architecture
TDWI White Paper: Multidomain Master Data Management
Improving Your Business by Mastering Multiple Data Domains
White Paper: Five Disruptive Trends in MDM
Podcast: Determining the Business Value of Multidomain MDM
Podcast: Where to Start in MDM
Webinar: MDM Business Case Success: Mastering Multiple Domains (with Forrester’s Rob Karel)
Composite Entities: Multi-Domain MDM in Action
Podcast: National Instruments' Journey to Complete Customer Management
Success Story: National Instruments on Data Consolidation as the Foundation for Improved Customer Relationships
Success Story: Leveraging Multidomain MDM to Manage Rapid Growth at Intuit
Multidomain MDM: Make Sure You Do the Homework First
White Paper: Master Data Management as “Plan B”
White Paper: Data Modeling & MDM
Podcast: MDM: Your Relationship Coach
Multi-Domain and Federated MDM Hubs: Two Key Considerations
Transforming Data Warehouses With SOA