There are two methods for adding controls to a map.
addControl(), passing in a single control object, or
addControls(), passing in an array of control objects.
When you create your map, four control objects are added automatically. These four controls are:
OpenLayers.Control.Navigation: Responsible for handling map interaction from mouse events, such as dragging the mouse, zooming with the scroll bar, and double-clicking.
OpenLayers.Control.PanZoom: Adds a Pan/Zoom bar to the top left hand side of the map. Contains up/down/left/right ...