Add all 36 Oreos to a food processor or blender. Pulse until they are fine crumbs. Use a spoon to stir everything up a bit if you get some stubborn ones that won't break down. (You can also do this with a ziplock and rolling pin.)

(If you want to sprinkle the tops of your dipped truffles with Oreo cookie crumbs, you can remove about 1/4 cup of crumbs at this point and set aside.)

Cut the cream cheese into several pieces. Make sure it is really soft. (If not, microwave on power level 1 for a minute or two. Don't warm it, just get it soft.)

Pulse or beat the cream cheese into the cookie crumbs until a soft mixture has formed.

Use your hands or a 1-inch cookie scoop to shape the mixture into 1 inch balls. If the mixture is too soft, put it in the fridge for 15-30 minutes.

Line up the balls on a baking sheet. Freeze until hardened, at least 30 minutes.

In a medium bowl, melt the chocolate in the microwave in 30 second increments, stirring each time. Melt until there are a few lumps of chocolate left, then stir until smooth. Be careful, chocolate scorches very easily!

You can use semi-sweet chocolate or white chocolate. If you are using white chocolate, try to find Almond Bark. It melts really nicely. You can find it at Walmart usually. White chocolate chips will work too, if you add shortening.

For the semi sweet, you can use semi sweet chocolate chips or chocolate candy melts, or a semi sweet chocolate bar (Ghirardelli, Guittard, Lindt, etc. Buy a well-known brand.) You will need to add 1-5 teaspoons shortening to the semi sweet mixture. You can add a little shortening to the white chocolate too, if necessary. You want the chocolate to be nice and thin. When you dip a spoon in it, the chocolate should drizzle off of it in a smooth, thin stream, not gloop off your spoon in dollops. Use your best judgement and add shortening 1 teaspoon at a time until it is the right texture. You can also use vegetable oil if you don't have shortening. 

Prepare a baking sheet with wax paper or parchment paper.

If you have an electric griddle, heat it to the lowest setting and then place at least 2 towels on top. Place your bowl of melted chocolate on top. 

Dip each of the Oreo balls in chocolate one at a time. There are several ways you can dip them. The most common way is to use a fork and a butter knife. Place a frozen truffle on the tines of your fork and dip in the chocolate. Use a spoon to drizzle chocolate over the top of the truffle to cover it (don't swirl it or your truffle will start to melt!) Once it is completely covered, lift the fork out of the chocolate and tap the fork on the edge of the bowl, letting the chocolate flow out through the tines of the fork. (If the chocolate is too thick to flow through the tines when you lift and tap the fork, add a bit more shortening or oil to the chocolate to make it thinner.) Use a butter knife to gently push the truffle onto your prepared baking sheet. 

Clean your fork with a towel or paper towels. Make sure there are no crumbs on your fork when you dip it again. 

The other dipping method that I tried was with toothpick. This was is a lot easier, but you end up with a hole in your truffle (that you can later cover up with chocolate drizzles or sprinkles if you want.) It's simple: poke the truffle with a toothpick and dip it in the chocolate, drizzling the top with your spoon. Place the truffle on your baking sheet with the toothpick still in it. Freeze until firm.

While the dipped truffles are hot, you can sprinkle the tops with Oreo crumbs or with sprinkles. Freeze or refrigerate until the chocolate shell is firm. 

Once the truffles are firm, you can decorate the top with more drizzled chocolate. Melt chocolate (or use any that is leftover), add to a ziplock bag, and snip the corner. Drizzle to your heart's content. 

Store truffles covered in the refrigerator.