Sarah,
 
What kind of hole (drilled or chipped?) and how large?  Here in Ecuador, the
prehistorics tended to use rather crudely chipped holes for some utilitarian
purposes and finely drilled holes for other more ornamental ones.  For example,
they chipped little holes just behind the lip of Porphyrobaphe iostoma,
presumably for the purpose of stringing them while collecting in the field, much
as one would string fish through the gills.  Likewise, they made fairly crude
holes just below the hinge of Lyropecten spp. and these valves were probably
used as kitchen scoops or spatulas (toasting corn?) with a string through the
hole for hanging it by the fire.  On the other hand, shells used for decorative
purposes (diverse types of beads and pendants) usually were made with well
finished drilled holes.  Some large (and even some medium sized) gastropods
had largish holes bashed in the side in order to cut the muscle and extract the
meat.  Some heavy species were supposedly drilled for use as net weights.  I
think another use for these could have been as the weights on "bolas" (like
those used by Argentine gauchos) for capturing sea birds.
 
In Ecuador, Conus were sometimes made into small containers that were
presumably used to hold the lime that is a necessary adjunct to the chewing of
coca leaves.  The anterior end of the shell was sawed off, the "innards"
removed, and the narrow aperture sealed off with some material (e.g., resin);
sometimes a little cap was made of some other shell material. These
containers sometimes had a hole so that they could be strung on a string.
 
We have also found Conus that were apparently used to smooth out and
enlarge round holes made in other shell artifacts, especially mother-of-pearl
disks that often had a large hole in the center.
 
kate