It would appear that Warner Bros. has cut two slightly different teaser trailers for Man of Steel. (Neither of which are the full trailer that was shown at San Diego Comic-Con.)
This one, the one I saw before The Dark Knight Rises, features a voiceover by Russell Crowe’s Jor-El:
And this one features a voiceover by Kevin Costner’s Jonathan Kent:
This teaser trailer did its job for me. I am officially slightly more excited than terrified for this film. Next summer can’t come fast enough!