You can view normal maps in Viewport 2.0 in textured mode. Press 6 to switch to textured display mode.
Display your normal map in tangent space map or object space
The existing bump2d nodes in your scene are found in the Utilities tab of the Hypershade Browser panel. See Build and create materials using the Hypershade.
To select the bump node for the shader network currently assigned to your object, select the object, then select Graph > Graph Materials on Selected Objects from the Hypershade menu. Select the bump2d node in the resulting graph in the Hypershade work area panel.