[The Hierophant]

This is just my crackpot theory, but even if Osama is dead, and even if the American administration knows he is dead, they arn't exactly going to go around telling everyone. Right now, the hunt for Osama is still political gold for the US war administration. They can get alot of really solid leverage by appealing to American citizen's hatred of terrorists, they need to keep this fire stoked and burning if they want to get the majority of their seeming middle-eastern objectives completed before the next election (a quelled Iraq, sedate Palestine etc). It makes sound political sense to keep 'alive' such a virile and widely-recognized political icon as Osama, even if in fact he really is 'dead'.