Currently, Amarok and Konversation are testing out git to help with KDE's migration. There are also one or two kde-related projects that have started on gitorious (although this is *not* recommended yet!)
First up, a brief description of the Gitorious.org user and permission model:
KDE currently operates the kde-developers and kde-sysadmin teams on Gitorious.org, as well as several <appname>-reviewers teams (e.g. konversation-reviewers. The purpose of each of these can best be illustrated by examining how a KDE project on Gitorious.org has to be set up:
Commit access is thus exclusively handled via kde-developers, and any member of kde-developers can commit to any KDE repository. Getting into kde-developers is done by filing a KDE sysadmin request against the gitorious component, which is then implemented by one of the administrators of the kde-developers team.
The kde-sysadmin team exists for the purpose of making sure KDE's sysadmin squad can edit all KDE repositories on Gitorious.org, to fix issues or help people in a bind.
The '<appname>-reviewers' teams were originally created to be able to remove the 'review' permission bit from kde-developers for all the repositories, because otherwise every kde-developers member got email notifications about every merge request for every project. So someone with no interest in Amarok or Konversation would still get MR mail about them. Project-specific reviewers teams solve that routing problem. The reviewers teams usually have all the core developers from a project as members, and are administrated by one or more key developers.
Now, about those optionally-added key developers with the 'admin' permission bit: Pushing a tag into a repository requires being allowed to do a "force push". Force pushing can be enabled/disabled on a per-repository basis on Gitorious.org by anyone who has the 'admin' permission bit for a repository. As outlined above, this currently means every member of the kde-sysadmin team - as well as one or more key developers from a given project that have been added individually with the 'admin' permission bit. Thus the the main motivation for this is to allow projects to push tags without having to involve KDE's sysadmin team.
FIXME: Is this a KDE project? Why are permissions not set for kde-developers?
http://gitorious.org/+kde-developers has a more up-to-date list of kde-run projects. However, that list includes projects that don't use kde frameworks (like KDE developers' personal projects), and experiments, and isn't sorted in any way. We plan to have a better directory of kde-related projects once git.kde.org is up.