Beat the egg whites until stiff. Beat the egg yolks with the sugar until frothy, then add the cream cheese. Melt the chocolate in a water bath and add it too (don`t stir too much). Finally fold in the egg whites and chill the mousse for 2 hours.
A word about chocolate: Leftovers from Easter bunnies or Santa Clauses are very suitable, but the mousse tastes better with good chocolate.