Post Tramutic Stress Disorder

Is there a support group for PTSD around here? I haven't see a forum for it and i'm really looking for people who can relate to being around someone with PTSD. I don't have PTSD, but a friend I recently met does. My only experienece with it was from a fairly serious relationship I was in where my boyfriend had severe PTSD from a childhood tramua. Obviously those situations are very different and I don't know what would help her...She also isn't really open about it so I don't think it would be okay to just ask what her triggers are so I can try to avoid them (like with my boyfriend I knew that I shouldn't ever lean across him, or if we were in a public place I never took the seat closest to the wall becasue that seat made him feel the safest).