Just figured this out today after trying once before. If you have a multi-monitor setup like I do you may like to have the console & debugger be in a separate window. Xcode 4 moved to a predominately single window interface which is a bummer for multi-monitor setups. I tried opening a new window and collapsing all but the debugger / console panes but the console wouldn’t take commands and was effectively useless..
Turns out there is a trick menu item: View -> Debug Area -> Activate Console
So with the cursor in the console in the second window, select the above mentioned menu item and Bingo! a working debug / console view in a separate window. sweet!
Now to file an enhancement request for a behavior to open a separate window and configure it like this automatically 🙂