The construction of large scale e-Science grid experiments presents a challenge to e-Scientists because of the inherent difficulty of deploying applications over large scale heterogeneous grids. In spite of this, user-oriented application deployment has remained unsupported in grid middleware. This lack of support for application deployment is strongly detrimental to the usability, evolution, uptake and continual development of the grid. This paper presents our motivation, design and implementation of the Distributed Ant user-oriented application deployment system, including recent extensions to support application deployment over heterogeneous grids. We also present a significant Distributed Ant deployment case study, demonstrating how a user-oriented application deployment system enables e-Science experiments.