Change the Primary Display on an iMac

I just got a really nice 21.6″ Samsung SyncMaster 216BW display the other day, and I wanted to use it as the primary display with my iMac. I wanted the menu bar and the dock to be on that display instead of the built-in display.

I had never thought to do this before, so I found it a little hard to figure out. What you need to do is open the Display Preference Pane, click on the Arrangement tab, and drag the little white menu bar from one display to the other.