Was just in Pittsburgh last week. I enjoyed Church Brew Works. I liked the atmosphere of drinking in an old church. I only had one beer called MM that was a tasty hoppy imperial stout.
My favourite Pittsburgh brewery is East End. You should try to make it out during their "Growler Hours" where you can sample a lot of their beers, plus buy growlers/bottles of many of them. I bought the Smoked Porter and Gratitude Barleywine and my friend bought growlers of 2 of their beers on tap. Look at their website for the hours:
For bars, I did a mini pub crawl down East Carson street. Starting east and going west you can go to:
Fathead's - 1805 E. Carson St., Pittsburgh (Amazing tap list. Loud, but fun atmosphere. Fairly good bottle selection available for purchase upstairs too.)
Pipers Pub - 1828 East Carson Street, Pittsburgh (Smaller, but really good tap list with more focus on local beers, though I did have a Great Divide Oak Aged Yeti on tap, so they do more than just local. The owner was saying he tries to get all local food too, but I didn't try any so can't comment on quality. Guy next to me at the bar said the food is a lot better than Fat Head's.)
Smokin' Joe's - 2001 East Carson Street, Pittsburgh (Very narrow bar, but very nice beer selection. I was probably fairly drunk by this point though.)
I didn't make it to my 4th desitnation, but it gets good reviews:
The Library - 2302 East Carson Street, Pittsburgh
Made it to Church Brew Works earlier this week. Fantastic setting; generally excellent beer (esp the case-conditioned pale ale). Would definitely go back. Bought a shirt even!
While I didn't make it to Penn Brewery, I did manage to try a couple of their beers available elsewhere. Very good as well.
I will look forward to the other great suggestions on a return trip.
I can't speak for Penn Brewery, but Church Brew Works just north of the Strip District is a fun place to visit (it's built inside an old church). I've had some fantastic seasonal beers there in the past - been several years since I was last there.
I go to Pittsburgh about once a year for either baseball or to go to the different museums etc and Penn Brewery is always a stop for me. Their beers are all classic German beers and are very highly regarded (but it doesn't matter as long as you like them and I do) I find their lunch menu to be a better value than their dinner menu. Don't forget to buy a case to take home; I always do, as I can't get their beer on LI.
I also like Fatheads on Carson St; great selection of beer on tap, and unbelievable sandwiches. I try not to follow the crowd, but one of their famous sandwiches is the Southside Slopes and it is a must order!; take a look at what it is on their website!.