I recently gave a talk to some fellow Canonical employees about where we are with the "Distributed Development" project. For that I made a screencast showing some of the Launchpad Codehosting features that you can now use for Ubuntu. Thanks to the Launchpad team for making this happen. We're still ironing out the remaining kinks that make it a pain to use, and getting all the packages imported, but it's possible to use them now.
The screencast has no audio unfortunately, but you can watch it and try and guess what I was saying. There's documentation available on the wiki as well.
One of the things the video shows is how to request someone review your change, i.e. how to get a change sponsored in to Ubuntu. I'm keen to have people test this, as it's not something I do very often now that I am a core-dev. Therefore if you want to help test then propose a merge and set the appropriate sponsor team as the reviewer, and I will prioritise it and you can give me feedback in return.
Note that a bug in Launchpad means that I won't get a notification when they are created, so feel free to drop me a line via email or on IRC until that bug is fixed next month. I'll continue to poll the lists though, so nothing will get dropped.