Michael Ledeen, who probably is better informed about goings-on in Iran than almost anybody, says that Osama is dead. According to Ledeen, citing "...Iranians I trust, Osama Bin Laden finally departed this world in mid-December."
The old murderer supposedly died of kidney failure and "...was buried in Iran, where he had spend most of his time" since the destruction of al Qaeda in Afghanistan. Ledeen says his Iranian sources pointed out that the usual Al Qaeda yearly message in connection with the Muslim Haj to Mecca came, for the first time this year, from that unpardonably late dinner guest, Ayman al-Zawahiri, and not Osama.
This information seems to make sense. Osama has not appeared in public in several years, and it would seem to be in his interest to do so, just to prove such death rumors wrong.
Of course, if he really IS alive, and wants to make a public appearance, a good venue would be a nice large open field in downtown Tehran, preferably in a group appearance with Iranian President Mahmoud "Mad Jad" Ahmadinejad and Iranian Supreme Leader Ayatollah Ali Khamenei. Maybe if we threw in a multi-course catered lunch, ol' al-Zawahiri would join them. I'm sure the USAF would be happy to provide lighting and entertainment.