class Schet(models.Model):
    nomer      = models.CharField("Номер счета",max_length = 10)
    document   = models.ImageField("Счет",upload_to = '/home/minotavr_x86/python/scheta/src/scheta/documents')
    date_in    = models.DateField("Дата создания")
    komu       = models.CharField("Для кого счет",max_length = 30, null=True)
    otdel      = models.IntegerField("Отдел",max_length = 3, null=True)
    na_chto    = models.CharField("Краткое описание",max_length = 40, null=True)
    scheta_prim = models.CharField("Примечание",max_length = 50, null=True)

class Way(models.Model):
    id_schet  = models.ForeignKey(Schet)
    id_people = models.ForeignKey(People)
    date      = models.DateField("Дата")
    podpis    = models.BooleanField("Подпись")
    stop      = models.BooleanField("Остановка счета")
    way_prim  = models.CharField("Примечания",max_length = 50, null=True)

scheta = Schet.objects.annotate(Max('way__date'))

...
 id_schet  = models.ForeignKey(Schet, related_name = way)
...

...
for schet in scheta:
    print schet.way   # результат - объект класса Way
...

scheta = Schet.objects.annotate(Max('way__date'))    
way = [el.way_set.all().annotate(Max('date')) for el in scheta]

scheta = Schet.objects.extra(tables = ['dbscheta_way'], select = {'max_date':'date','stop':'dbscheta_way.stop','way_prim':'way_prim'},
                                 where = ['date = (Select MAX(date) FROM dbscheta_way WHERE dbscheta_way.id_schet_id=dbscheta_schet.id) '] )