CD Projekt has been cautious about a potential console release of The Witcher 2 for some time, though it's aware of the size of the console audience. Given the very warm critical reception The Witcher 2 has received so far, a console port would probably be a safe bet. It's also worth noting that the PC version already plays well with a controller -- the menus even reflect Xbox 360 button mapping when using an Xbox 360 controller.
Update: The ESRB has removed Xbox 360 as a platform in its Witcher 2 listing. We've reached out to CD Projekt for comment.
Update 2: CD Projekt has responded to Joystiq, saying, "We've said for some time that we'd love to bring The Witcher 2 to consoles, but we haven't made any announcements to that effect. Our focus has been and continues to be on the PC version. We're going to be showing off something at E3, and we'll announce what that is shortly before the show."