Yes. Milk, half and half and buttermilk can all be frozen. A good way to do this is to fill muffin tins with the dairy product and freeze. Once frozen, pop them out and place the portions into freezer bags. Once thawed the products may have separated. Simply place in a blender for a second or two to re-homogenize the product.

Additional Resources:
http://www.ag.ndsu.edu/pubs/yf/foods/fnw616.htm