Migrations[0] are being included in Django 1.7 which is currently under development. For those unaware, Andrew Godwin, the author of South, ran a successful Kickstarter campaign[1] the fund this effort to incorporate migrations in Django core.
[0] https://docs.djangoproject.com/en/dev/topics/migrations/
[1] http://www.kickstarter.com/projects/andrewgodwin/schema-migr...