What it really means is that it's time for you, Twisted users who care about Python 3, to contribute patches that port specific modules to Python 3. Our development infrastructure is now set up to efficiently deal with such patches, and to keep modules working once they're ported.
- We have a buildbot set up to run a subset of the tests on Python 3.
- There is a list of supported modules that can be updated as new modules are ported, to ensure they keep working. Most of the modules which are particularly tricky have now been ported, so contributors should now just need to do the tedious work of examining each module for small things that need to be addressed.
- There's a tool that the buildbot runs, which all Twisted developers (including you) can run to verify that everything is working properly on 3.x if you have a functioning local Python 3.3 installation. (This tool is an interim step until Trial itself is fully ported to 3.x.)
- There's a milestone you can look at containing a list of tasks for python 3.x, although this list is not exhaustive. If you come up with some work that needs to be done to port a module to python 3, put the ticket in that milestone.
So, if you're interested in using Twisted for a project that runs on Python 3, it should be pretty quick to port the functionality you need and submit a patch.