A new report has surfaced stating that the Half-Blood Prince teaser trailer will be released on May 16th. This rumour states that the preview will make its debut before the Narnia Prince Caspian film.

We are trying to get confirmation from Warner Brothers.

Source: The Leaky Cauldron

UPDATE: Warner Bros. has stated that nothing is confirmed at the present time. We will keep you updated with news about the teaser trailer when we receive it.