In most cases, if there is any load balancing to be done it's done by the application itself. So if I have an application that is like namd, it will do the load balancing for me. I don't have to worry about doing anything special. If I have an application that I am writing, obviously I can put as much in the way of load balancing as I want into it. If I have an application that's a parameter sweep type application, where I basically launch the same application on, say, a dozen different nodes with a dozen different data sets, it would be up to me, the person running it, to make sure that the data sets were similar enough so that I had some sort of load balancing. But I haven't seen too many applications, or I should say utilities, for doing load balancing except for, you know, estimating the amount of time a given application is going to run on a given node, and then I just manually say, "OK, I can see how I can do this."