This paper discusses automated methods to achieve web service advertisement and discovery, and presents efficient search and matching techniques based on OWL-S. The service discovery and matchmaking is performed via a centralized peer-to-peer web service repository. The repository has the ability to run on a software cloud, which improves the availability and scalability of the service discovery. An OWL-S based unified ontology Suggested Upper Merged Ontology is used in web service annotation. User-agents generate query specification using the system ontology, to provide semantic unification between the client and the system during service discovery. Query matching is performed via complex Hilbert Spaces composed of conceptual planes and categorical similarities for each web service.