UPDATE: As expected, Sony have since confirmed The Last Of Us: Remastered for PS4, with the promise of more details to be shared shortly.
Original Story follows:
Note that the above banner ad in the PSN store links to a "Page Not Found" error, which suggests that this information has been leaked ahead of time and will likely be taken down soon. Either way, The Last of Us for PS3 was one of the best games of last year, and a remastered version for PS4 would be welcomed. It seems like it's only a matter of time until this is announced officially, so more details will likely be coming soon.