According to this post on the Infinity Ward forums, we can expect some kind of announcement from the Call of Duty developer next Saturday.

Amazing Things To Happen On April 28th: 1758 - James Monroe, 5th President of the United States is born. 1788 - Maryland becomes the seventh state to ratify the Constitution of the United States. 1932 - A vaccine for yellow fever is announced for use on humans. (Then nothing really happened for a long time.... but now....) 2007 - What goes down this April 28th is equal to, if not surpasses, the magnitude of any of those.Whose ready?!