class UsAddress(models.Model):
    #other fields
    zip = us_models.USPostalCodeField()
    country = models.CharField(max_length=2)
    phone = us_models.PhoneNumberField()

    def __unicode__(self):
        return  self.zip + self.country + self.phone


class MyType(models.Model):
    code = models.IntegerField()
    address = UsAddress

    def __unicode__(self):
        return str(self.code) + " - " + unicode(self.address) #self.address.__unicode__()

<MyType: 219 - <class 'web.models.UsAddress'>>

mt = models.ForeignKey(MyType)

class MyType(models.Model):
    code = models.IntegerField()
    address = UsAddress

    def __unicode__(self):
        return u'%s - %s' % (self.code, self.address)

<p>My object: {{ mytype_obj }}</p>