How to make an overview window of the whole level with location of the player

Hello,
i want to make an overview popupwindow or HUD when the player walks throu the area and presses a specific key. Then the whole level should show up in the HUD and an arrow should indicate the location of the player. So he knows where he is.
Is there a turorial for this outside?
Thanks in advance for any help.
Best
einar