Up until now we only knew that the PlayStation 4 would launch before Christmas 2013, but at Sony's Gamescom press conference they have announced that PS4 will launch on November 15th in USA and November 29th in Europe.
ony PS4 coming Nov 15 in USA & Nov 29 in Europe
You can start getting exited. Sony’s new PlayStation 4 will be available to buy in stores from November 15th in USA and two weeks later on November 29th in Europe. PS4 will launch in 32 countries.

PlayStation 4 will be available this November
At launch several game titles will be available, including previously announced titles such as Fifa 14, Watch Dogs, Battlefield 4, Call of Duty: Ghosts, Drive Club, Killzone Shadow Fall, and Assassin's Creed IV. At Gamescom Sony also presented games such as Shadow of the Beast, Minecraft, War Thunder, as well as exclusive extra content for Assassin's Creed IV and Watch Dogs.
You can still pre-order your PlayStation 4 online but it will also be available on retail floors on launch day for $399, €399 or £349, depending on your region. Sony says that more than 1 million PS4 consoles have been pre-ordered so far. More about the PlayStation 4 here.