Service Oriented Architecture - best practices

On the SOA Institute.org site are many interesting articles about SOA architecture best practices like:

SOA Governance for the Organization: Best Practices for Getting Started
Avoiding SOA Security Anti-Patterns: Practical Planning for Success
SOA Architecture Considerations
Flexibility by Design: Adapting to Changes at Run-Time in SOA Implementations

For some white papers or articles you have to register, but the registration is free.