Rocs!

Social Network Visualizer (SocNetV) is a cross-platform, user-friendly application for the analysis and visualization of Social Networks in the form of mathematical graphs, where vertices depict actors/agents and edges represent their relations.

GraphShop is the Graph Theory Workshop, an interactive software environment for Graph Theory research and applications. It contains a visual "point and click" interface for graph creation and manipulations, as well as an integrated scripting environment (using ECMAScript) linked both ways with the GUI systems. This means that one can create a graph with scripting, examine and modify it with the visual interface, and then run a custom script algorithm on the result.

the free and opensource(GPL) software framework to work on graphs and social networks.

GraphThing is a tool that allows you to create, manipulate and study graphs. These "graphs" are mathematical objects that describe relationships between sets; they are not 2D plots, charts, or anything similar to that.

Rin'G is an environment for the study and implementation of Graph Theory algorithms that allows users to view interactive, step-by-step animations of their executions.

Create weighted and unweighted graphs and run algorithms step by step. Learn graph theory interactively… much better than a book!