Osama bin Laden probably is dead.
One thing's for sure -- that wasn't him who appears on that video as orthodox Islam expressly forbids dyeing the hair black:
http://www.witness-pioneer.org/vil/hadeeth/riyad/17/chap294.htm
Thus, we learn that except for inevitable circumstances...
Islamic jurisprudence forbids men and women to dye their hair black "except when the intention is jihad...as a show of strength to unbelievers" ('Umdat al-Salik e.4.4).
http://www.jihadwatch.org/archives/018075.php