A full translation of the just released audio-taped message credited to Osama bin Laden is available (without subscription or other cost) from the blog Informed Comment.
Whatever else may be said, bin Laden (or whoever) does have a sense of audience. In this case, his intended audience is the American people. The arguments and evidence are organized for our ears and expectations. There are far-left and far-right leaders in the United States who could be quoted saying 80 to 90 percent of what bin Laden offers in these brief remarks.
For someone who, we suppose, is constantly on the move from one safehouse to another in the most rugged and isolated region of Afpak with very limited staff support, the remarks demonstrate significant familiarity with American debates over the wars and our relationship with Israel. Very few American leaders would be as adept in discussing a similar range of issues related to the Arab world.
My best guess is that the first draft of the script was produced by Adam Yahiye Gadahn. The reformed death metalist, early web-surfer, and one time California boy is apparently continuing to google from somewhere in the Hindu Kush.