django-formwizard is a reusable app to work with multi-page forms. Besides normal Forms, it supports FormSets and ModelForms. File uploads don't work at the moment but this will be fixed in the near future.
To install it, simply run
# pip install django-formwizard
The source is available on GitHub.
If you are interested in contributing, just fork the repository on GitHub and commit your changes. Don't forget to send a pull request.