Karen, points.com is a site that has deals with many points programs. You can register your goldpoints there, and any other frequent flyer or other program that they have a deal with. I have my Aeroplan miles there, and Gold points. They do AAAdvantage as well, I think. Some of their partners haven't signed up for the "full monty", i.e., swap, buy, sell, redeem. Northwest is one of those--which is a drag, because I have some miles that I would love to swap to Aeroplan, but can't. They take a cut, I presume.
They have a new thing coming in December called "GPX", Global Points Exchange. It's supposed to be a marketplace for exchaning points with other people. Interesting, wonder how well it will work! I thought most points programs prohibited this type of thing.