those who continue to announce “It is I” have traditional grammatical correctness on their side, but they are vastly outnumbered by those who proudly boast “it’s me!” There’s not much that can be done about this now. Similarly, if a caller asks for Susan and Susan answers “This is she,” her somewhat antiquated correctness is likely to startle the questioner into confusion.
http://www.wsu.edu/~brians/errors/myself.html