CD Projeckt RED confirmed release date for Witcher 2. The game will be released on a May 17, 2011. Here is a quote:

"We’ve decided to move the launch date back a few weeks to afford us more time to polish the game” – said Adam Badowski, project lead at CD Projekt RED. “Of course, we know that players would like to get the game as soon as possible, so we hope that they will forgive us! We strongly believe that the extra time spent polishing the title will be well worth the wait."