The ​http://code.djangoproject.com/browser/django/branches/gis gis branch intends add a contrib app implementing geographic support.

Alternatives

Custom Manager

A custom manager (and queryset) to support lookups like:

Schools.objects.filter(geom__overlaps=bbox.geom)   # &&

Schools.objects.filter(geom__contains=bbox.geom)  # ~

Schools.objects.filter(geom__sameas=bbox.geom)  # ~=

Schools.objects.filter(geom__inside=bbox.geom)  # @

Field Types

Field type for a geometry

GIS wrapper

wrapper for geos, have the ability to do something like

from django.contrib.gis import area
area(bbox.geom)

... more to come :P