Django is the lagging project, actually. Most smaller projects have already bitten the bullet.
At my last Django meetup, we did a show of hands of who was waiting for Django to move before personally switching over to Python 3, and it was basically everyone.
Yep, now people will be waiting for "that Django library that doesn't work with Python 3". Hopefully those are much fewer. I'll start experimenting with 3 when 1.5 us released, I hear it's the default on ubuntu 12.10, but I might be wrong (I should check).
It's installed by default in 12.10, alongside Python 2.7. Eventually, only Python 3 will be in a default installation, but it will still use the command 'python3'.
I'm hopeful that these will be updated around the same time or moving to Python 3 won't be an option for most people. I suspect most Django apps are based on MySQL.
Most that I've encountered have been PostgreSQL or MySQL. I've seen a few sqlite3 and oracle backed sites in the wild as well. I think I've seen more redis and more mongo sites than I've seen firebird.
At my last Django meetup, we did a show of hands of who was waiting for Django to move before personally switching over to Python 3, and it was basically everyone.