Hi, It depends on what exactly you'd like to do with the data. If it's a really nice basic visualization, and a few typical network statistics (like different kinds of centrality, modularity), then Gephi is probably a great place to start - link . You can upload file to it from a wide variety of formats.
Otherwise, for more complicated analyses, I'd say go with UCINET link (which you can use for 30 days free). Indeed, you could analyse the data in UCINET and then visualize it in Gephi.
For learning UCINET, and social networks more generally, see Hanneman's text book at link