Django Lock allows you to lock down either individual views or your whole site.

You have the option of an administrative preview password and the options to lock down until a date is reached and/or only start locking down some time in the future.

See the readme for more

Project frozen

If you're looking to use this in a new project, I recommend trying django-lockdown instead: http://bitbucket.org/carljm/django-lockdown/src

This project will sit around as I'm using it in a few projects (and others may be too). It could potentially receive bug fixes too.

So yeah, use django-lockdown for new projects - I helped add some bits of missing functionality to that so now it has all the potential of django-lock and more.