http://arstechnica.com/gaming/2015/11/the-ps4-can-now-emulate-playstation-2-games/?mbid=synd_moz_videogamesgen1
Sony's been hiding it for a while, but apparently they've developed their own PS2 emulator that runs natively on the PS4, and boasts a healthy emulation and positive impact on the games so far.
This makes me really happy, because I have some older PS2 games (Star Ocean 3, Champions of Norath) that I wouldn't mind seeing at 60fps with anti-aliasing...