Service-oriented Computing (SOC) is becoming the leading paradigm for the creation of agile and flexible enterprise IT infrastructures. Services, as the key elements of SOC, can be composed in very efficient way to support flexible business processes and to adapt application systems quickly to new business requirements. However, these applications need to be tested, monitored and maintained; thus, the management aspect of Service-oriented infrastructures is often neglected. Therefore, we propose a Service Management System that enhances the management of infrastructures for SOC and describes a first step towards the self-management of services. Furthermore, this paper provides a core set of components and required management functions that must be considered in providing a Service Management System for Service-oriented systems.