I don't have the time to track it down. To be honest I'm not sure who the leaker was, but it's widely reported there indeed was a leak:
How does he communicate?
His biggest problem remains communications, which the United States has successfully compromised during his time in Afghanistan. For a time, he used satellite phones, but that ended after a leak revealed that the U.S. was listening in.
http://www.msnbc.com/news/627355.asp
Also:
Those leaks are serious blows because the window closes and you can't see what's going on inside the house anymore," Smith said, citing a 1998 leak revealing that terrorist Usama bin Laden's satellite phone was being monitored by the United States. Afterward, bin Laden ceased using the telephone.
http://www.globalsecurity.org/org/news/2002/020703-fbi1.htm