It was first revealed during Sony's E3 press conference, and we were told it was coming this summer.
Now, however, we may have an exact date. If you check the PlayStation Store, you'll see that the "First Light" downloadable content for inFamous: Second Son has an August 26 date.
This expansion features Abigail Walker, the Conduit in the game who comes to be known as Fetch. Walker relives dark memories while locked in a prison for Conduits, so we imagine there will be plenty of flashback missions. I'm happy to give it a try, as Neon was my favorite power in the game (just 'cuz I wanted to be all Good). This DLC will retail for $15 and remember that it's a standalone expansion, so you don't need inFamous: Second Son to play it.
Honestly, though, why would you want to play a piece of DLC if you haven't played the game?
Related Game(s): inFamous: Second Son