Discovering web services is the process of finding web services that satisfy specific requirements. Rich and formal representations of services and interactions are required for principled selection of services, context-aware analysis and satisfaction of requests, as well as dynamic interaction and negotiation with the service providers. Semantic technologies facilitate specialization and generalization of service needs as well as service composition. Thus, a higher degree of automation and more precise results can be achieved. In this paper, we provide a review of current Semantic Web Service (SWS) discovery approaches.