I Googled "homeschool Pittsburgh," and here are the first few things that popped up:
http://homeschooling.about.com/od/pasg/p/pasgpaah.htmhttp://www.parentzone.com/usa/penns...s/for-your-child/education/homeschoolinghttp://www.pahomeschoolers.com/calendar.html (Note that there's a homeschool workshop and curriculum fair on March 21 in Pittsburgh! I'll bet that would be a great place to go, ask questions and network!)
http://www.city-data.com/forum/pittsburgh/166135-pgh-south-hills-homeschool-cyberschool-group.htmlhttp://homeschooling.gomilpitas.com/regional/PennsylvaniaSupport.htmhttp://www.nphep.org/http://pittsburgh.about.com/od/homeschooling/Home_Schooling_in_Pittsburgh.htmThere's loads more links, but this seemed like a good start for you. I'll bet you dollars to donuts there's something in there that would work.
No pressure, but I'm with RJH that if the social thing is all that worries you, then I think you need to do more research before you rule out homeschooling.
You may still rule it out. That's fair. But not because there's nothing social available.