Network Analysis with igraph by Gábor Csárdi.
I saw this mentioned on Christophe Lalanne’s Bag of Tweets for March 2012 and wanted to insert a word of caution.
While it is true that the igraph documentation page also points to the “Network Analysis with igraph” page as being “under development,” a number of sections are not done at all.
The most recent copyright date is 2006.
Just be aware that igraph 0.3.2 was released in December of 2006. The latest version of igraph is 0.5.4, released in August of 2010.
For your convenience: igraph at Sourceforge, development version at Launchpad.