Dear moet, this option (a hotkey 0) was available in debug version only. If you'd like to turn on a free view you can do it by switching to 3d side control mode (while you controling the vessels with the mouse).
It depends on what are you looking for while you are playing the game. If you'd like to get a global experience, then strategic map is your choice. In case you are a fan of the real dynamic action - welcome to 3D side with manual controls.
Of course, at any time you can switch from strategic map to 3D.