The new Office Garage Series
Microsoft provides tools to import and synchronize user objects from an existing Active Directory environment, perform bulk CSV list imports or use custom PowerShell scripts to populate the identity store with User Principle Names and required directory attributes.
The final frontier from an automation perspective is really to set up ADFS and single sign-on as a way to ensure that your policies for password updates and the service authentication itself integrates with your existing tools and policies. The best place to go for all of this is the Office 365 deployment center on TechNet. It walks you through the right solution depending on your organization size and needs.
More Resources:
Manage Windows Azure Active Directory by using Windows PowerShell
Directory synchronization roadmap
Garage Series for IT Pros Archive of previous episodes
Office 365 TechCenter on TechNet
