While I could not confirm the veracity of the tape, I did find one NY Times article in Lexis Nexis that confirms Clinton did speak to the Long Island Association on Feb. 15, 2002. I would place my bets on this tape being authentic.
I will be doing some legwork to contact sources mentioned in the piece to see if I can't get a transcript of his comments or something along those lines.
Further info:
According to the Newsday archived story on this, Clinton did talk about terrorism (though I didn't want to pay to read the whole thing, so I don't know what specifically).
It is looking more and more likely like Newsmax did obtain a legit tape here.
Everyone KNOWS he lies. The people who voted for him don't care.