In a food processor, crush the cookies until you have fine crumbs. Add the cream cheese and process until mixture is thick and pasty and fully incorporated. (Note that if you are using a cookie with cream filling such as Oreos, you may need slightly less cream cheese than with a cookie with no cream filling.)
Scoop the filling into a bowl, cover with plastic wrap, and refrigerate for 1-2 hours. Form into balls (this will make 36-48 truffles, depending on how big or small you make them). Melt the chocolate according to the instructions on the package. Dip the balls in the melted chocolate, chocolate chips, sugar, etc, then place on a baking sheet covered with wax paper. Top the truffles with sprinkles, or whatever decoration you would like. Chill for about an hour before serving, and store leftovers (if there are any!) in the fridge.
Original Blog Post: http://www.curlygirlkitchen.com/2011/07/oreo-truffles.html