Melt chocolate in the microwave on LOW {or defrost. It's very important that you don't overcook the chocolate. Start with one minute, stir, and then continue in 30 second intervals, stirring well in between
In a blender, combine ice, milk, ice cream, and chocolate mixture {NOTE: If you don't have a powerful blender, you'll likely need to dislodge the ice cubes frequently until they start to become crushed}. Blend until smooth.