This bar is AMAZING. I visited Pittsburgh for the first time recently with the girlfriend and she took me to Belvedere's to see Gang Green and some really really awesome local bands. Needless to say I was in heaven. The beer was cheap and delicious and we got free shots from a bartender that looked exactly like Jesus would if he bar-tended (I shit you not, not only was this fellow the most benevolent bartender I have ever met but his hair was flowing and divine and probably magical).
The bar is:
A dirt hole, it's grunge filled, it's the definition of a dive.
If you have delicate sensibilities I would stop in to check it out, spend money, but not stay.
This place is a great place to see punk shows. It's the last of a dieing breed.