I found this on the howtoeatacupcake blog. I haven't tried it myself but the reviews were great. Here are some tips: To have perfectly smooth cream cheese frosting with enough body to spread in dramatic swirls or even pipe through a pastry bag, you have to know these two secrets. First, overbeating breaks down the cream cheese, and produces grainy looking frosting that is too soft to hold a shape. Second, cold (not softened) cream cheese produces the best texture in both of our methods. Have the butter, if you use it, at the temperature recommended for the method you choose, and sift the powdered sugar after measuring.