There is a critical need to design and develop tools that abstract away the fundamental complexity of XML based Web services specifications and toolkits, and provide an elegant, intuitive, simple, and powerful query based invocation system to end users. Web services based tools and standards have been designed to facilitate seamless integration and development for application developers. As a result, current implementations require the end user to have intimate knowledge of Web services and related toolkits, and users often play an informed role in the overall Web services execution process We employ a set of algorithms and optimizations to match user queries with corresponding operations in Web services, invoke the operations with the correct set of parameters, and present the results to the end user. Our system uses the Semantic Web and Ontologies in the process of automating Web services invocation and execution.1