Social Networks Visualiser (SocNetV) is an Social Networks Analysis tool for Linux, Mac and Windows written in Qt4. It is a graphical application designed to be an easy tool for Social Networks Analysis and Visualisation. With it, you can load and visualise networks of various formats (GraphViz, Adjacency, Pajek, etc), and/or visually create and modify a network using your mouse.
The application is being developed in C++ with the Qt GUI development toolkit, for Linux, but you can compile and run it on OS X and Windows as well, as long as you have Qt installed. Currently SocNetV is being developed in Qt4, and from now on is licensed under the GNU Public Licence version 3 (GPL3).
To see SocNetV in action, you need a modern Linux distro with the Qt4 library installed. It is very easy to compile from the source code (there are no dependencies, except the presence of Qt 4 libraries).
More info at the project’s homepage.