Preheat oven to 325 degrees.  Cream together the butter, icing sugar and vanilla in a medium sized bowl.  In a separate bowl combine the flour and baking soda, add to the creamed mixture and stir.  Add the rolled oats and chocolate chips.  Roll dough into walnut sized balls and place on an un-greased cookie sheet 2 inches apart.  Flatten balls with a fork and bake for 10-12 minutes.  Remove from cookie sheet to wire rack to cool!  Enjoy!