The PS4 companion application, titled simply PlayStation App, has launched in the States in time for the release of the next-generation console on Friday 15 November.
At present, it is unavailable for download in the UK or other regions, but we expect that to change as the later 29 November release of the PS4 nears.
If you are in the US, you can download it for free now from iTunes for iPhone, iPod touch and iPad and Google Play for Android devices. It offers all manner of second-screen experiences for supported games and allows remote access to your PSN Friends, including details on what games they are playing and the ability to chat with them without having to turn on your console.
You can also browse and buy games from the PlayStation Store and push them to your own PS4. They will then be ready when you get home, says Sony.
The PlayStation App only works with the PS4 and a valid Sony Entertainment Network account, so you can't use it with a PS3 or PS Vita.