Hi Guzzo,
I used
Phpizabi in the past to build a site called "TheNewMommy.com. It had all the features of myspace and a little bit more. Best of all the script is free. It was a little hard to customize though.
Now I use
Joomla to build my own social networking sites from almost scratch. With Joomla you can install a plug-in called "Community Builder" and it gives you a base social networking platform. Then there are a bunch of add-ons to CB that make it even better.
With Joomla I have created a site that has:
Live Chat
Forum
Online Store
Video Library
Audio Library
Downloads Section
Member Blogs
Member Profiles
Internal Private Messaging
Rating and Reviews For All Content
Paid Subscription Business Model
Affiliate Program
and Marketplace (Member Classifieds)
All of this was on one site @ JuggernautClub.com it took me about a week to setup and I got all the extensions I needed for it for less then $100.
I hope this helps...