On the NPR radio program Wait Wait Don't Tell Me (http://www.npr.org/programs/wait-wait-dont-tell-me/) Peter Sagal introduces the week's panelists using 'it's,' as in "She'll be performing Friday at the Comedy Club, it's Paula Poundstone." I'm not sure it is grammatically incorrect, but it doesn't seem appropriate to refer to a person as "it." Wouldn't it be better to say "she is" in this case? Or better yet, use another phrase, such as "we welcome..." or "say hello to..?"
I have heard similar usage on other radio and television programming as well when the gender is known to the speaker, where "it is" replaces "she/he is/has." Is this now acceptable usage?