He isn’t hunkered down in a cave. He is probably set up in a nice house somewhere in either Pakistan (being protected by elements of the government), or he is in Iran. Since the bin Laden family has shipping interests, he could be anywhere—Somalia, Yemen, a remote Indonesian island, or even Saudi.
I’m not so sure about that: http://www.nydailynews.com/news/us_world/2009/03/14/2009-03-14_where_is_osama_bin_laden_us_zeros_in_on_.html