If you want to obtain latitude and longitude in Google Maps, you can do the following (from Obtaining Geographic Coordinates):
Find the place you require coordinates for, and double click on it to centre the map around that point. Then click the "link to this page" link, and the coordinates (in degrees and parts of a degree in decimals) appear in the address bar, eg "http://maps.google.co.uk/?ll=51.455558,-2.605047&spn=0.032304,0.069523". In this case the latitude is 51.455558, and the longitude is -2.605047. The reverse is possible by entering the lat and long into the search bar, with a space between them.
Another way is to go to http://pagesperso-orange.fr/universimmedia/geo/loc.htm