A while ago, the Psi development team switched from Darcs to Subversion for version control, because the Darcs pros (distributed, extremely simple and elegant) did not compensate for the cons any longer (slowness, non-scalability, ‘infinite’ merges, lack of community and tools, …). Our development was pretty central anyway at that time, so we decided that Subversion was good enough. However, we started to miss local commits more than we thought we would, and some of us are working on their own forks, which makes Subversion a suboptimal choice. We are therefore currently trying out Git as a replacement, which should bring us all the good stuff from Darcs, combined with the speed and portability of Subversion. Note that during the experiment, we will not be updating our Subversion branch any more (which will soon cause breakage, since Subversion automatically updates changes to the external Iris repository).
If you're interested in following our latest developments from our experimental Git tree, simply clone our official repository through the following steps:
If you're interested in knowing more about using Git, check out Scott Chacon's excellent Git talk (and accompanying book).
For fans of social networking, we also have a mirror of the official Psi repository on GitHub. And while we're on the topic of web interfaces: while waiting for an official web interface to our Git repository, you can check out an experimental one here.