OpenLayers.Control.LayerSwitcher

This control will by default display a small image in the upper right corner of the map. When clicked, this image expands into a control which allows one to select between multiple types of layers, seperated into two types: Base Layers and Overlays. Only one base layer can be selected at a time, and is enforced by a radio button control being used. Multiple overlays can be selected at once, and a checkbox control is visible for this functionality.
* Constructor
  OpenLayers.Control.LayerSwitcher({Object|options}?) -- Creates a new control.

* Methods
  maximizeControl() -- none -- Expand the layer switcher control.
  minimizeControl() -- none -- Close the layer switcher control.

* Parameters
  position -- (inherited from {OpenLayers.Control}) {OpenLayers.Pixel} to use as the top-left corner of the control div, relative to the map area.
  activeColor -- The color to use for the background of the layer switcher div.
  ascending -- Ascending determines whether layers are added to the layer switcher in ascending or descending order. If ascending is true, the lowest layer is appended to the list first. If ascending is false, the lowest layer is at the very bottom of the LayerSwitcher. Default is true.