While working on modernization of large monolithic application; speed , synchronization and interaction with other components are the major concern for practical implementation of target system; as Service-Oriented Computing extends and covering many sections of monolithic legacy to web oriented development, these aspects becoming a new challenges to existing software engineering practices, the paper presents work which is undertaken for service orientation of monolithic legacy application including initial steps of service understanding, comprehension and extraction so that it can take a part in further migration activities to service oriented architecture platform. The work also shows that how several useful techniques can be applied to accomplish the result.