I have found a point of interest in Google Maps (using the most recent Firefox).
How to get its coordinates?
you can use the Google Maps Labs addon called LatLng Marker - go to the lower left corner to Maps Labs and in following window enable the above mentioned addon:
Now you can add the coordinate marker anywhere you want using right mouse click and selecting it in context menu. A marker with coordinates will appear on your map and it is easy to copy the coordinates from it.
Once you have selected the point of interest, if you get the link to the map (the button right next to the print map option), the last two comma separated values in the link or HTML code specify its coordinates.
There are many third party sites to do this as well such as http://itouchmap.com/latlong.html, http://universimmedia.pagesperso-orange.fr/geo/loc.htm, etc.
Place the point of interest in the center.
Firefox menu > Developer tools > Scratchpad
Paste this code:
Right-click and click "Run".
A popup appears, showing the coordinates.