That's the next step - authors of 3rd party apps will need to port their code. We've started putting together some documentation to help authors write single-source code (i.e. code that runs on both 2.6+ and 3.2+). The idea is that they'll use the tools we did, plus the things we learned, to port their apps. https://docs.djangoproject.com/en/dev/topics/python3/ is a start on that documentation, and hopefully we can flesh it out even more for 1.5.

Obviously the Django ecosystem can't start supporting Python 3 until Django itself does.

The porting process (which is still in progress for Django) shouldn't be too difficult for most pluggable applications, as Django strongly encourages using unicode everywhere.