Software for networks analysis
The igraph package (http://igraph.sourceforge.net/) is a must-have. It includes basic network generators, efficient and reliable algorithms for statistical analysis - shortest pathes, clustering, centrality, etc. Stores graphs in a sparse way. Exists as a C library, a python one, and a R package. This last one is very efficient and convenient. See doc here: http://igraph.sourceforge.net/docum....
SIENA, from Tom Snidjers, is devoted to the statistical analysis of longitudinal social network data (dynamics networks) http://stat.gamma.rug.nl/siena.html.
The wikipedia page http://en.wikipedia.org/wiki/Social... lists (too ?) many softs, most of them being able to perform statistical analysis.
Networks generation
The nauty set of programs (http://cs.anu.edu.au/~bdm/nauty/), written by Brendan McKay, contains geng a marvellous tool able to generate all the possible networks of size N in a very efficient way. It is even able to generate only non-isomorphic networks (see the manual).
More software
Also see a list of software there: http://www.wikiviz.org/wiki/Tools