Agna 
(Applied Graph & Network Analysis) is a tool built for social network analysis, sociometry and sequential analysis. With Agna you can study relationships between groups, relationships between people, and the structure of social networks. The results are graphed nicely so that you can simply see the results of your analysis.
It uses network analysis which assumes that the way that people communicate affects important properties of that group. Here nodes are people and edges are communication acts. It also uses sequential analysis which identifies the constants and rules that govern the inner structure.
It was developed by Marius I. Benta, a PhD student at University College Cork (Ireland).
It’s a free download (windows, Mac, Linux), and you can see more screenshots here.
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