Grid is a computing and data management infrastructure whose goal is to provide electronic underpinning for a global society in business, government, research, science and entertainment. Being a distributed system, grid is complex due to the heterogeneous nature of the underlying software and hardware resources forming it. The heterogeneous nature of grid will hinder interoperation of grid applications. The purpose of this paper is to develop a model for communication among grid applications in spite of its distributed and heterogeneous nature. To realize this aim, we conducted an extensive review of existing implementation solutions for managing and integrating heterogeneous distributed applications. We used the knowledge gained from the literature to develop a model for integrating heterogeneous grid applications, and to implement the model designed.