Abstract: The emerging trends of Semantic web attract the attention of researchers, due to the increased level of machine understandability which could offer an enhanced approach of acquiring more relevant results. It leads to redefining of the existing conventional web services (Web 2.0) into semantic web services (Web 3.0).The Conventional WSDL Services (Web Service Definition Language) are mapped into the semantic based OWL-S Services (Web Ontology Language for Services) through the addition of Semantic Annotations. This paper clearly focuses on giving a detailed overview of Semantic web, thereby states the need for redefinition of Web2.0.It stands as a guide to the researchers to gain an additional knowledge and for the beginners, a stepping stone into the semantic web research.