Spaces, Leopard's virtual desktop feature, is excellent for expanding your desktop by up to 16 workspaces, however, it would be really cool if you could assign specific applications to always open in the same space. Well, you can!
All you have to do is open the Spaces preference pane (Apple Menu > System Preferences > Exposé and Spaces > Spaces tab). Once there, just drag the application you would like to add to the specific space in the overview pane.
You can also add applications by using the list below the spaces overview, which is also how you remove the application assignments (just click the application in the list and then click the minus button).