Seen this behind the counter today at Gamestation. I asked the lady behind the counter when it started and she wasn't too sure but thought maybe it was for Saturday.
When you buy GOW2 you get the option to then buy the wireless adaptor for £30. This is great for those who preordered because unfortunately it looks like it might be pretty difficult to get the game on release day without a preorder.
Oh and I did ask about RRP of GOW2 in Gamestation and they said they will not know until midnight tonight when it goes live.