I'm pretty sure I heard of this one, but I hadn't seen the full text, which Denis DeKat has kindly provided. There are real subversives lurking in the heart of Islamic wild-assness, Saudi Arabia. ("Fundamentalism" is a term with a specific meaning, and we do not muddy the waters by misusing it.) I recommend reading the piece through; it's a fine satire, even if a bit too long.
It's only right and proper that serious-minded Islamists have taken the supposed authors to task for religious extremism; only to be expected that some others would have seriously taken it to heart, but in fact there seems to be no reason to believe that anyone has. Those who want to criticize the Saudi commentators for gullibility will do well to look up Report from Iron Mountain, but there is a difference: there are Americans who have taken that satire seriously and liked it.
(Do I believe the interpretation I've just given, or am I being sarcastic? Yes. I mean, mostly the former.)
Update: For contrast, read this, which looks entirely like the real thing, even when presented by a site that surely is violently hostile to Islamism.