Architectural Methodologies and Models:

• High level comparison of some SOA methodologies
• List of (Service Oriented) Enterprise Architecture Frameworks
  • ISO/ITU-T/IEC : Reference Model of Open Distributed Computing (RM-ODP) : Overview, Foundation, Architecture and Semantics
  • Open Group : The Open Group Architecture Framework - TOGAF
    

Interoperabilty:

• HL7 : Service Aware Interoperabilty Framework (SAIF)

Readings:

• Software Engineering Institute : Evaluating a SOA
• Software Engineering Institute : Architecting Service-Oriented Systems

Additional Resources:

• OMG : SoaML 

• Open Group : The SOA Ontology 2.0
• HL7 Healthcare Service Ontology