It seems that the Associated Press believe that they are the copyright owners of the photo which the Obama presidential campaign poster created by Shepard Fairey was based on. AP's lawyers are now in touch with Fairey's lawyers over the matter of credit and compensation.
Yet just a couple of weeks ago, James Dazinger at least, seemed to think that the photo had been taken Reuters photographer, Jim Young. I note though that he's since blogged that the photo was taken by freelance photojournalist Manny Garcia for AP.
Update: It appears Manny Garcia wasn't a member of AP staff when he took the photo and he, not AP, may be the copyright owner.
Update: See: http://prawfsblawg.blogs.com/prawfsblawg/2009/01/a-question-for-ip-folks.html and http://madisonian.net/2009/01/21/fairey-obama-and-fair-use/ for informed commentary.