I haven't lived in the area for the past few years, but back then, the SS Nightmare at Station Square wasn't too bad. I know there are better ones, I just haven't gone to any others yet.
I haven't been out in a few years, but there used ot be a great one held down in New Kensington.......can't recall the street it was on, but I am sure you can find it through a Google search.
This is probably too late, but Scare House is really good. You can see them featured on the Travel Channels top 10 scariest attractions show each year. Be sure to catch them next year!