Mapping Tool
   
   
Instructions
Drag the red marker (centre) to display the grid reference for your location.

The grid refs will appear on the right, with corresponding grid squares on the map.

Press the Satellite button to turn on the aerial photos, or Hybrid for both maps and aerials (top right).

Use the + and - buttons (top left) to zoom in and out, and the arrows to pan.
Credits
Many thanks go to Keith Balmer for sharing the code for this mapping tool originally used on the excellent Bedfordshire Natural History Society web site.

(The javascript in this application is released under the GNU General Public License Version 2)