To find coordinates for the plugin you can use:

• Google Earth
  In Google Earth you can set the coordinates to decimals instead of degrees, minutes' and seconds":
  • Go to menu tools then submenu options.
  • Then tab 3D view and group "Show Lat/Long".

• The coordinates of your own GPS or navigator.
• In maps.google.com you can search for an address and then enter in the address bar of your browser to get coordinates: javascript:void(prompt('',gApplication.getMap().getCenter()));

• In maps.google.com you can select to show the link. Make sure that the marker is in the center and then click on link to this page. Get the coordinates for the parameter ll out of the url.

Keep in mind that negative longitude is for America (left of the United Kingdom) and negative latitude for Africa (below equator)