PGHComedy.com has everything you could possibly want to know about comedy happening in and around Pittsburgh. Open Mic Nights (there is one pretty much every night), booked shows with local comedians, improv comedy shows, links to comedian's websites, information on touring comedians who are coming to town like Louis CK and Jeff Dunham!
Also, there is original content and links to work by local comedians. Pittsburgh has a unique and special community of comedians who all know each other, and encourage each other in their work. PGHComedy.com is really an online hub to support and foster that community. So check it out at PGHComedy.com and don't forget the follow them on twitter @PGHComedy and on facebook!