Continuing the game exactly were "S.T.A.L.K.E.R.: Shadow of Chernobyl" ended, "S.T.A.L.K.E.R.: Call of Pripyat" got its own official web site now which you can find here. Using GSC Game World's own game engine, the X-Ray engine v.1.6, it is supposed to increase the graphical details of the game even further.
Besides screenshots and a few hints regarding the story, you can also find some interesting new features of the game: