Ask H&T: Wedding Registry
http://www.100layercake.com/blog/2013/05/16/astoria-road-a-wedding-registry-that-lets-you-add-gifts-from-any-store/
http://www.100layercake.com/blog/2013/02/28/simpleregistry/
http://www.100layercake.com/blog/2012/08/18/registry-love/