Just in case anyone still thinks this is a movement based around a charismatic leader, and not an ideology that is larger than any one person. From [1] AP, with thanks to Ali Dashti:

WASHINGTON – The top American commander in Afghanistan said Tuesday he has no evidence Osama bin Laden is in day-to-day control of al-Qaeda but suggested the long-absent terrorist leader is alive.

Lt. Gen. David Barno, speaking to reporters during a visit to the Pentagon, talked mostly of a lack of evidence about bin Laden's whereabouts, health and current role in the al-Qaeda network. He remains, however, a critical target, Barno said.

Still, "I don't see any indications that he is in day-to-day command and control, as it were, of the al-Qaeda organization or the other terrorist groups that work with him, certainly in the Afghanistan-Pakistan area," Barno said.

Barno suggested that bin Laden's death would be difficult to conceal from intelligence services, even if he died in a secret place, because his associates would talk about it. Recent communications from al-Qaeda's top echelon have come from bin Laden's chief deputy, Ayman al-Zawahri, as videotaped messages.