1. A method for managing available resources in a grid computing environment that includes a plurality of computing clusters, the method comprising the steps of: when a new job is submitted, determining if a first of the computing clusters has sufficient available resources to run the new job; if the first computing cluster does not have sufficient available resources to run the new job, determining if a second of the computing clusters has sufficient available resources to run a first job that is currently running on the first computing cluster; if the second computing cluster has sufficient available resources to run the first job, migrating the first job to the second computing cluster; and after migrating the first job to the second computing cluster, if the first computer cluster still does not have sufficient available resources to run the new job, migrating a second job that is currently running on the first computing cluster to the second computing cluster or to a third of the computer clusters and running the new job on the first computing cluster.