Recently, some of cellular phones in the market are equipped with wireless local communication devices such as infrared, Bluetooth, and a contactless IC chip, and several companies are trying to launch real-world mobile commerce services. However, the services have not become widespread yet. In order to realize the market penetration of the services, this research focuses on the mechanism for enhancing users? convenience and service flexibility. In the architecture proposed in this paper, a service execution engine in a user?s cellular phone works as a common platform for multiple services. It automatically installs and updates service data stored in the cellular phone if necessary (called service plug-and-play). Based on the proposed architecture, we have developed a platform for real-world mobile commerce (called LightHolder) and have evaluated it through the development of several prototype services.