The realization of complex distributed applications, required in areas such as e-Business, e-Government, and ambient intelligence, calls for new development paradigms, such as the Service Oriented Computing approach which accommodates for dynamic and adaptive interaction schemata, carried on on a per-to-peer level. Multi Agent Systems offer the natural architectural solutions to several requirements imposed by such an adaptive approach. This work discusses the limitation of common agent patterns, typically adopted in distributed information systems design, when applied to service oriented computing, and introduces two novel agent patterns, that we call Service Oriented Organization and Implicit Organization Broker agent pattern, respectively. Some design aspects of the Implicit Organization Broker agent pattern are also presented. The limitations and the proposed solutions are demonstrated in the development of a multi agent system which implements a pervasive museum visitors guide. Some of the architecture and design features serve as a reference scenario for the demonstration of both the current methods limitations and the contribution of the newly proposed agent patterns and associated communication framework.