tapioca-qt
tapioca-qt is a Qt4 package containing high-level classes on top of TelepathyQt for use in clients. It's used in at least decibel and kopete experimental telepathy branch.
Telepathy-Qt4 is a more up-to-date library providing similar functionality.
Development branch
The current version is in svn: svn co https://svn.sourceforge.net/svnroot/tapioca-voip/trunk/tapioca-qt
More info can be found at http://tapioca-voip.sourceforge.net/wiki