I am picking up inFamous from the PSN store once it is back up. 
I have one question about the free running. Is it more like Assassin's Creed or Prototype or completely different?

It's a little ''stickier'' (trying to simply drop down the side of a building can be a hassle) but otherwise still makes the game really fun to maneuverer about (skating across electricity lines is immensely satisfying), and Cole doesn't take any fall damage so there's little punishment for missing a jump. 

it's like sly cooper

Well, it's more like Assassin's Creed than Prototype, but a more accurate comparison would be to The Saboteur, if you ever played that. The sides of buildings are covered with parts that stick out that you can grab, and you hit the jump button to move from part to part, occasionally doing something like shimmying along a ledge in order to get to another part to the side. Apparently they've streamlined this in inFamous 2, some buildings now have power cables running down the sides, and you can just grab on and ride the current all the way to the top.

@Abyssfull: Do you press a specific button to start free running like in AC or is it natural?

@Abyssfull: Do you press a specific button to start free running like in AC or is it natural?

@Abyssfull: Do you press a specific button to start free running like in AC or is it natural?

The climbing is you repeatedly pressing X to jump from ledge to ledge. The jumping and gliding is kind of like in Prototype, only not nearly as extreme (you can't jump like the Hulk or glide-fly several hundred meters).

You basically spam X and point where you want to go.

It feels a lot smoother than AC's.