Gephi is an open-source software for graph and network analysis. It uses a 3D render engine to display large graphs in real-time and to speed up the exploration. Gephi combines built-in functionalities and flexible architecture to:
export all types of networks.
Gephi is based on a visualize-and-manipulate paradigm which allow any user to discover networks and data properties. Moreover, it is designed to follow the chain of a case study, from data file to nice printable maps. Gephi is a free/libre software distributed under the GPL 3 ("GNU General Public License"). Runs on Windows, Linux and Mac OS X. Gephi is open-source and free.