I am interested in finding the latitude and longitude of a point on a map. How do I do so in Google Maps?
In Google Maps Labs are two features which can do that.
Displays a tooltip next to the mouse cursor showing the latlng directly underneath it.
Adds an option to the context menu that lets you drop a mini marker showing the latlng of the position that the cursor was pointing at when the context menu was evoked
If you right click on the map and select 'What's Here?' from the context menu, a marker will appear and the coordinates will be placed in the search box at the top of the page.
You can also just click the "Link" button on the upper right hand corner above the map. This will generate a link that will contain the latitude and longitude of the center of the map as a query string parameter call "ll".
There's a maplet extension you can add your "my maps" called "GPS Location" If you add that to your map and then click on a point. It will add a pin with the GPS info on it