From One Body, One Spirit:
"..In addition, it has been announced that the popular Memorial Acclamation, "Christ has died. Christ is risen. Christ will come again," is no longer an option in the Order of Mass. This had been an American adaptation to the 1985 Roman Missal and the inclusion of this acclamation had been in doubt since it was not in the Latin typical edition.
The Missal will be available for use in Advent 2011. The study text will be posted on the USCCB website soon at www.usccb.org/romanmissal.
A more complete article from Catholic News Service is available here."