A major challenge in the field of location- based service (LBS) system engineering, is to establish a highly scalable system architecture which can be instantiated in moderate-size configurations handling thousands of moving items as well as in upper-end configurations handling millions of moving items. We are exploring an approach of using a cluster of database server nodes and effecting efficient distributed and parallel computing in both real-time update of location records of moving items and processing of location- related queries. The approach of developing efficient middleware which is layered on a cluster of nodes running commercial off-the-shelf database servers, has been adopted. The middleware design is substantially based on the TMO scheme for real-time distributed object programming and real-time distributed computing system design, which enables low-overhead coordination of distributed computations and highly abstract distributed programming styles.