http://www.ostube.de/en/ostube and http://www.phpmotion.com/ and http://www.socialengine.net/ or http://www.webscribble.com/ or a few script from here http://www.boonex.com/products/ and the big community was go, http://www.phpizabi.net/ thats all i have know... Repp is appriciated
I have seen a few others within www.sourceforge.net library, matter to run a query for "social network"
And if you want to read reviews about some of those scripts mentioned above check my website: MyTestBox.com Hope it helps you...