Yes, there was a CO President's Club in the North Concourse when GSO was a hub (it was the old Eastern club). Im surprised (like mersk862) that the rates are higher in the South Concourse. It would make sense to have CO there and make it a "STAR alliance" terminal (at least useful for lounge access or the occasional connection...believe it or not, they do happen sometimes!).

The US Club is very nice at GSO, recently remodeled. The lounge ladies are wonderful too!