First-Person Shooter Style Navigation

When active, move with the arrow keys; alternately, hold 'Shift' and move with WASD.
Movement is restricted to the X-Y Plane.  Pressing Shift + Q will move you down in the Z direction, and Shift + E will move you up.
Left-click the mouse and hold to look around.
Right-click and hold, and you will move 10 times as fast.