So will PS4 games in 3D? Short answer is maybe. Long answer is that it's really depends on the game, it's up to the developer to decide whether or not they want to add 3D functionality to their games.
It is also up to number of other factors. Do you have a television that is compatible with 3D? Do you have the 3D glasses for it? All these things need to line up. The PS3 officially supports 3D games so it's absolutely possible but it will boil down whether or not the games are specifically made to be 3D compatible.
And looking at trend of industry, I think the Sony really try to make 3D a thing with the PS3 toward the end of its life span but you'll seeing a lot less of that with the PS4. So while, by no means an official answer, I think you gonna see a lot less 3D games a the years go on.