In this paper, we introduce MPI-style Web service (MPIWS), a novel service presented as a standard Web service but integrated with MPI programming technologies to allow Web applications to run in parallel over a loosely coupled distributed environment. MPIWS takes advantage of the SOAP communication protocol, and allows direct MPI-style communication among loosely coupled services. The MPI-style communication supported by MPIWS includes both point-to-point and collective communications. In this paper, point-to-point and collective communication operations are evaluated in comparison with mpiJava. The evaluation results demonstrate that although the overhead of SOAP messaging takes a toll on performance, MPIWS is generally comparable with mpiJava sending Object data types, especially for coarse-grain applications, and outperforms mpiJava in some cases.