GTAGaming posted several images of a map for Grand Theft Auto IV's streets and subway system. As for the authenticity of the Liberty City map, well ... that's a whole other issue. The six images are of varying clarity and one image even shows the PS3 controls for the game.
A few things raised red flags for us with the images, like one image showing Liberty City "neighbourhoods" -- with a "u." Although this map could be for an international version of the game, it still seems odd that a map depicting an alternate version of New York City would spell neighborhood in an un-American fashion. Another issue is some awkwardly constructed sentences in the region details (like the first sentence in the Alderney description). We're sure people may find other things to make their spidey sense tingle, but check it out and make your own conclusions about authenticity.
Update: Images pulled, kbai.