Lois Lowry, a children's book writer, has updated her online blog with information about The Giver movie. She had hoped Order of the Phoenix and Half-Blood Prince director David Yates would be able to direct The Giver. However:
…he has just decided he wants to do the final Harry Potter first, thereby postponing The Giver by several years.
While this is not confirmed by Warner Brothers yet, it appears to be a pretty reliable source. We'll let you know if we know more. Thanks to Ms. Lowry and Leaky for the tip!