Project Goals: Matching the requirements of users and their applications to the distributed heterogeneous resources that comprise the Computational Grid is essential for its effective exploitation by the e-Scientist. To do this we need to be able to: Describe a job as a sequence of inter-related and potentially dependent tasks. Optimise the placement of these tasks distributed resources to minimise execution time through a community scheduler. Explore the use of simple computational economics to influence placement decisions. Demonstrate this infrastructure using application usage scenarios from High Energy Physics and other domains. This work is taking place within the service oriented architectures that exist within the EU DataGrid and ICENI (the Imperial College e-Science Networked Infrastructure) through the use of the Open Grid Services Architecture.