Example for Box Hill.
Find it on GoogleEarth:
Zoom in enough to see the car park and put the cursor (usually a hand) on the car park entrance.
Read co-ordinates at the bottom of the screen:
51 deg 15.353' N 0 deg 19.344' W
If you need a different format for the co-ordinates, select it here:
(Tools - Options from the main toolbar to get to this menu)
That should do you.
Originally Posted by Endurodude
Maybe I'm just a luddite!
If you have a Garmin 550 you're definitely not a Luddite. I'm still using my 15-year old Garmin GPSII.
(So I know how to load it with googleEarth co-ordinates, it's the only way to put a route on it!)