Valve has confirmed that its awesome-looking sequel Portal 2 will allow PS3 owners to play with their PC and Mac brethren in a cross-platform setup that will also include chat options.
After you load up the game on PS3 and sign into your Steam account you'll have PC/Mac players listed to start playing with.
As a nice touch and to get you rocking the co-op, Valve is offering PS3 players with a Steam account the chance to download a free version of Portal 2 onto their PC.