mohammedatta@hotmail.com

Not sure this is accurate, but if so it's an interesting detail:

We all know by now that many of the alleged hijackers made no efforts to conceal their identities or activities as they moved about the country before 9/11, even though a number of them were already on terrorist watch lists, or were being closely monitored by programs like Able Danger. This point is really hammered home by something a friend of mine turned up not too long ago: in a document from the Zacharias Moussaoui trial there is a listing of real name usages by various hijackers. Among these, which I find quite hilarious, is the fact that Atta's e-mail address was mohammedatta@hotmail.com.