I have used :
http://www.getlatlon.com/
when finding points on maps for gps, I believe there is an addon for google that will do it, but get latlong is simple, position the curser, read off the bottom of the page, make sure you dont confuse which is which, minus numbers are possibly west of greenwich , some gps's need an E or W before the number and not the minus, you will have to play. hope this helps.
I did some plotting in France (poi's) and realy confused my self with the minus business, parts of the south west are west of greenwich