Also, some people are speculating that it is the guy from the Subway in the game. It doesn't look like him from the times I watched it. The guy in the subway is also someone important as he is in the trailer for the third one and in the subway he spurts:
72 Hours, 72 Hours...Thats how long Zion lasted the last time
Niobe: Who are you?
Me, I'm just a...spectator...
Something along those lines at least. People have also been saying that it was the Architect in disguise, but I cant see that either because from the evidence (in the first film and 2nd) he can view anything he wants in the matrix, he doesnt have to anywhere.