Using a food processor or zip lock bag and kitchen mallet, crush Oreos (use entire package) until they are fine crumbs. Place the Oreo crumbs into a large mixing bowl. Add the block of cream cheese in the mixing bowl and combine the crumbs and cream cheese together using your hands. Mash/mix Oreos and cream cheese together until you have a big compact oreo/cream cheese ball with very little cream cheese showing. Scoop out little 1 inch balls with your hands and roll them around making sure they are smooth and round. Place Oreo balls onto a plate or baking sheet and allow them to chill is the freezer for at least 30 minutes. Once Oreo balls are chilled you can melt your chocolate either using the microwave or double broiler method. Dip Oreo balls into the melted chocolate and use a fork to scoop them out and let the excess chocolate drip off. Place truffles on a plate or baking sheet lined with parchment paper. If you want to decorate your truffles with sprinkles or Oreo crumbs add those while the chocolate is still wet. Return truffles back to the refrigerator to set for another 15-20 minutes. Once they are dry they are ready to serve.