The PS4 versions will be available as free downloads later this year; the PS4 itself is set to launch this holiday season.
PlanetSide 2 is a Windows PC-exclusive free-to-play MMO first-person shooter, while the superhero MMO DC Universe Online is available on PC and PlayStation 3. PlanetSide 2 launched as a free-to-play game last November, whereas DC Universe Online was released in January 2011 and became free-to-play in November of that year.
DC Universe Online does not support cross-platform play between its PS3 and PC versions. We've reached out to Sony Online Entertainment to ask if the same is true of the PS4 versions of DC Universe Online and PlanetSide 2, and will update this article with any information we receive.
Update: Sony Online Entertainment released trailers advertising the PS4 versions of both games this afternoon. It's unclear if the trailers contain PS4 footage.
DC Universe Online