Употребляют. "you got mail"(вы получили (только что)письмо). uses the simple past tense, and therefore would report that you received mail in the past. For example, "Today I finally got some mail! I haven't had any for days!" But in the case of being informed/finding that the present situation has changed due to an event in the past, one must use the present perfect tense.
present perfect tense "You have mail!"(письмо тебя ждёт)используется меньше.
"You've got mail" thus can be interpreted two ways:
"You have got(possess) mail (waiting for you to read)" (informal)
"You have(possess) mail (waiting for you to read)" (formal)
or
"You have got(have received) mail(, which is waiting for you to read)"
(...however, I believe 'gotten' is not used for the 'receive' meaning of 'get'..?)
http://www.englishforums.com/search/have%20got.htm