In Django 1.5, extending the existing User model has been introduced. You can use this directly to add new fields.
But if you are using a previous version of Django, then do the following:
Create a new model called Profile
and put all your required fields there.
from django.contrib.auth.models import User
class Profile(models.Model):
user = models.OneToOneField(User)
...
Then in your settings file, add:
AUTH_PROFILE_MODULE = '<application_name>.Profile'
where application_name is the name of app in which you've created Profile
model.
When you have a signed in user, you can use request.user.get_profile()
to fetch the corresponding Profile object.