I'm putting this in Camping It Up rather than GPS but happy for it to be moved if more appropriate.
I just stumbled on this
http://www.cycletourer.co.uk/cycletouring/custompois.shtml which is a good article and have downloaded the Arches Camping GPS on to my Garmin Etrex - I'm amazed at so many campsites.
Has anyone used this and if so any highlights/issues with it or tips?