I would imagine Mr. Bettag could shed a lot of light on this.  Did he confirm that Cindy Sheehan's letter was altered?  If Bettag could confirm this many people owe Cindy Sheehan an apology!!!

UPDATE:

Hitchens is continuing to claim that quote from the letter is genuine (today on C-SPAN). He calls Sheehan a liar for disavowing the quote.

Somebody needs to get ABC to make a definitive statement. I've posted a message to the board where the alleged letter was posted. I don't expect much, but one can always hope.

Hitchens owes no apology because the evidence now available indicates that the email is genuine and that Sheehan is lying about it.  She could resolve the matter herself by producing her own copy and giving details about who faked the email and how it was done.  Instead, she seeks to cut off any inquiry with her stonewalling "enough about that" response.  It seems quite unlikely that she would protect someone who supposedly is misrepresenting her views.  The shrill rhetoric in the email is consistent with other public statements Sheehan has made, most notoriously at an April 2005 rally for Lynne Stewart.  Moreover, it is quite common for the loved ones of soldiers to be familiar with military terms, and Sheehan has had more reason than most to learn as much as she can about her son's service.

http://www.redstate.org/story/2005/8/18/175654/041

http://mrzine.monthlyreview.org/ferner090805.html

http://www.frontpagemag.com/Articles/ReadArticle.asp?ID=19195

Sheehan bears the same relation to the current anti-war movement as Jane Fonda did to the movement against the Vietnam War--a loose cannon who out of emotion or foolishness seems to be embracing the full spectrum of "blame America first" left-wing lunacy.  Those who really want a change in policy, including Democratic Party leaders, would be well-advised to stear clear of Sheehan.

I think it is pretty clear that Hitchens is close-to-the-edge (to put it politely) and assumes his ridiculous stands simply for calculated shock-value. Apparently still incensed at the Nation editors who once dared question his innate genius, he has degenerated into a contrarian buffoon, an Orwell in his own mind. A beleaguered, heroic champion of hard-boiled truth who alone has the mustard to stand up to the outrages of the "Left" in its defilement of the likewise beleaguered, heroic Bush administration. But quite unlike Orwell, Hitchens has mutated into a queer establishmentarian who feeds off inner rage of a personal sort. He increasingly resorts to shrill, dismissive onslaughts against chimeric opponents. Thus Cindy Sheehan, distilled through the mind of Christopher Hitchens, becomes a clear-and-present-danger, an imminent threat to Western Civilization. He seems assured that Americans are so impressed with his artful use of the English language that it hardly matters what he is actually saying, so long as he talks tough. Which is no doubt why he is doing it here instead of in the UK, where he is rightly seen as a demented, pompous asshole. Over here, demented, pompous assholes thrive like never before, and in a brilliant career move, Hitchens has indeed joined political and rhetorical company with some of the top media intellectuals, like Hannity, Matthews, Scarborough & Blitzer.