n00bs on Ubuntu shows you how to use the Place Windows Compiz Plugin on Ubuntu 11.04

Here is a guide that will explain how to create window placement rules, with these rules you can assign a workspace to a program. So Evolution opens on workspace 2, the update manager on workspace 3 and so on. To use this option you need to have the CompizConfig Settings Manager installed. This option can be useful for people with smaller screens.

  How To Use Place Windows Compiz Plugin On Ubuntu 11.04