I’m somewhat sure this is a real AP story, “Al-Qaida No. 2 says 9/11 theory propagated by Iran.” The Onion scooped them, with “9/11 Conspiracy Theories ‘Ridiculous,’ Al Qaeda Says.”
Unfortunately, no progress on the “fake tape” issue:
The authenticity of the two-hour audio recording posted on an Islamic Web site could not be independently confirmed. But the voice sounded like past audiotapes from the terror leader, and the posting where it was found bore the logo of Al-Sahab, al-Qaida’s official media arm.
(Via Orin Kerr at Volokh.)