Nowadays, semantic integration constitutes an important approach to deal with heterogeneity within large and dynamic enterprises. Currently, the existing solutions are mainly based on the use of some standards and also middlewares in order to overcome the integration problem. These solutions generally fail as they do not scale to large number of applications and also fail as they do not provide more flexibility and agility. Here, solutions based on semantic web services are promising and they are being actively researched. The paper outlines the potential role that these technologies can offer in solving some key challenges such as semantic mediation and interoperation. In particular, the paper proposes a flexible approach called ODSOI (Ontology-Driven Service-Oriented Integration) that combines both service-oriented architectures and ontologies and that aims to deal correctly with some application integration issues.