Find your way to the Summit, by steam, diesel, or shanks mare. (NO visits via the internet) Head for the very top, and place your GPS receiver where I'm pointing with my left hand in the picture. Determine the the location with care, as you would in placing an ordinary cache. Log your results, including Latitude, Longitude, Elevation (note whether GPS or barometric) and any other details, including GPS make and model, operating mode (battery saver, WAAS, etc.), average or instant reading, etc., and any other details you care to include. When there are enough entries, I'll try to summarize them in a log note.
PS: Didn't think about establishing this cache until after we came down, so don't have all of the information myself!
Modified October 2008: I finally got around to collecting the coordinates that have been posted. There were 26 of them, but I have thrown out a few readings that were obviously wrong. I've posted the results as a photo. NEW: There have been so many logs that it became much too much work to reduce all of the data. Finders can compare their results with others by consulting the log. It seems that the GPSRs have much improved accuracy in the six years since the cache was first published.
Added 6 October 2008: You will receive a point on www.summitcaching.org.uk for logging this cache.
Rockville, MD USA