From Washington Post:
When Osama Bin Laden wants to deliver a speech, a trusted video cameraman is summoned to a safe house somewhere in Pakistan, according to U.S. counterterrorism officials and analysts. The video file is then edited, stored on a tiny computer memory stick and given to a human courier. The memory stick usually passes through several sets of hands to disguise its route, until an operative finally sits down in an Internet cafe and saves the data to a password-protected Web site, they said.
Read the entire article here