Just in case anyone is looking for an answer, here is the solution i've found here:
http://demongin.org/blog/806/
To summarize:
He had an Essay table as follows:
from django.contrib.auth.models import User
class Essay(models.Model):
title = models.CharField(max_length=666)
body = models.TextField()
author = models.ForeignKey(User, null=True, blank=True)
where multiuser can create essays, so he created a admin.ModelAdmin class as follows:
from myapplication.essay.models import Essay
from django.contrib import admin
class EssayAdmin(admin.ModelAdmin):
list_display = ('title', 'author')
fieldsets = [
(None, { 'fields': [('title','body')] } ),
]
def save_model(self, request, obj, form, change):
if getattr(obj, 'author', None) is None:
obj.author = request.user
obj.save()