I was just researching this topic yesterday. Here is a link I found to some of the PA statutes:
http://members.aol.com/StatutesP7/18PA913.html
Just because you can carry (i.e. open or inside a county building) doesn't, IMO make it
wise to do so.
The frequent questions I see posted about "may I carry concealed here or there" seem to be ignoring the fact that you're carrying
concealed. I have (each time) inadvertently carried my weapon into buildings or other areas that are restricted or posted. I attribute this to being used to always wearing a gun and, of course, the comfort of the holster I use.