In this research project, support by Argonne National Laboratory with DARPA funds for the GLOBUS project, we will continue to research and develop methods for predicting the time that a job must wait in the queue prior to execution. We will conduct extensive experiments with trace data from Argonne National Laboratory, Cornell Theory Center and NCSA to determine the accuracy of different prediction methods. We will incorporate the prediction methodology into a tool for co-scheduling in a distributed system environment.