I do recall using wireless hotspots at the Swan and Dolphin when I was there for a trade show. I don't remember if they were free or not, but I was able to access them from the lobby of both hotels.
Not sure about anywhere else, but I would imagine that many of the DTD hotels would have wireless hotspots. I know that Hilton/Doubletree properties almost always have wireless hotspots set up in their lobbies.