photo/models.py:

    # (c) CareerGrub - http://www.careergrub.com - Interactive Media and Web Technology Jobs


    from common.models import City, State, Country, Region

    class Photo(models.Model):
        # this could be a Region, Country, State, City, 
        object_type = models.ForeignKey(ContentType, null=True, blank=True)
        object_id = models.PositiveIntegerField(null=True, blank=True)
        content_object = generic.GenericForeignKey("object_type", "object_id")    


templates/admin/photo/photo/change_form.html:

    # (c) CareerGrub - http://www.careergrub.com - Interactive Media and Web Technology Jobs
    {% extends "admin/change_form.html" %}

    {% block extrahead %}{{ block.super }}
    <script type="text/javascript" src="/site_media/js/jquery-1.2.6.min.js"></script>
    <script>
     $(document).ready(function(){
    	 $(".object_id").append("<div id='lookup_box'></div>");
	 $("#id_object_type").change(function () {
          var type = $("#id_object_type option:selected").text();
          var good_choice = true;
          if (type == 'city' || type == 'state' || type == 'country' || type == 'region') {
			  var link_root = '../../../common/';
			  $("#lookup_box").html("<a onclick='return showRelatedObjectLookupPopup(this);' id='lookup_id_object_id' class='related-lookup' href='../../../common/region/'>lookup</a>");
	          $("#lookup_id_object_id").text("Lookup " + type);
	          $("#lookup_id_object_id").attr('href', link_root + type + '/');
          } else {
          	  $("#lookup_box").html("<span class='related-lookup' style='color: red;'>Invalid Choice! - Pick City, State, Country or Region</span>");
          }
        })
        .change();

     });
    </script>
    
    {% endblock %}