While I have never built a social network before, I am unsure if you need anything outside the modules that Drupal offers. However, I do have a link to Drupal that gives a list of various different modules to help create a social network: Social Network Resources
This looks fairly complete, so my guess is that you will not need anything else.
Okay Scott. Thank you for the link. I will attempt the project now. But do I need any other skills to boot? PHP, e.t.c?