If you'd like to contribute to IPython (http://ipython.scipy.org, and http://launchpad.net/ipython on Launchpad), simply request membership on this team. For this team we (the core IPython developers) will approve membership to anyone who requests it without any requirements whatsoever, allowing potential contributors to share branches and collaborate with the core team. We do encourage you to join the IPython-dev mailing list though (http://mail.scipy.org/mailman/listinfo/ipython-dev), since that is where the actual discussions about IPython development take place.

If you want to share work on a branch with other contributors, simply make sure you assign the Launchpad ipython-contrib team as its owner instead of making it private. This will enable both you and other team members to write to the branch.

Members of the core IPython developer team (http://launchpad.net/~ipython-dev) have write access to the main IPython repository, and therefore membership in that team is approved only for contributors who have an established track record on the mailing list. While Launchpad makes it very easy for any individual to contribute a branch to any project, it's not so convenient for people to collaborate on branches they can't write to. That's why we created this team, so the barrier to newcomers to create branches that they can collaborate with the core developers on is as low as possible.

When you join this team, your membership is initially open for 3 months. After that period, you'll get a link that will let you (without having to ask anyone else) renew in periods of one year. So if after your initial try you find yourself engaged with the project, it's just one click to extend that membership (once per year). This policy makes it very easy to join and stay in, while having the team prune itself from people who may have moved on to other things after their initial involvement.