Has anyone used the IKEA registry? It is based out of the Pittsburgh store, but from what I've read anyone can use it. (If the guests buy something in a store other than Pittsburgh though- it won't show up on your registry that someone bought it I think- so your guests would need to just buy online from the Pittsburgh website)
http://ikeapittsburgh.com/gift-registry/Let me know if you have had any experiences with using this. We love IKEA!