Just as in the first game, and I completed that both on PC and on console without noticing any difficulty change so I don't see what you're going on about, starting to wonder if you even played the first one.

The first one co-op was possible as the puzzles were fairly stop and go till the end. From what I've seen for P2, the puzzles are between 5 and 10 times faster and accuracy will be vastly needed. Unless a PS3 user is using a mouse and keyboard or Razer makes a controller for the PS3 with their hypersensitive buttons there will be no balance.

Does it support local co-op?

Anyway we could still play it together on the couch, one on the laptop the other on the ps3. I guess using a trackpad and a dualshock will pretty much be equal.

Hopefully Valve will have some kind of deal on steam if you buy both the ps3 and pc version.

not lessened, irrelevent =)

has move support been confirmed?

I played through the first Portal using my laptop's touchpad mouse.

PS3 users will do just fine.

PC fanboys and PS3 fanboys dont get along...