That place in Bloomfield would be Crazy Mocha
http://www.crazymocha.com/ Several locations in town, local chain. Because one of those is at the library, that might make for a good place to work. Caution, they allow smoking at the Bloomfield location.
Anywhere downtown has 2 hours of free wireless now, although getting a signal inside could be tricky. I've tried to join that network from inside my office, and it hasn't worked. Not sure if some laptops with better antennas might work, though. If you're near a window and near one of the access points for that, it might work. Buying up for more time only costs $14.99 for a month ($7.99 for a day). Here's the info with coverage area
http://downtownpittsburgh.com/aboutP...ittsburgh.aspx
All the Paneras should have free wireless, as noted.
http://www.panera.com/ All the Starbucks and Borders have T-Mobile Hotspot which is not very cost effective unless you already subscribe.
We might be able to narrow it a bit more if you say an area of town you'd like to be near. It's not the easiest place to get around, and recommending places that are far away (Panera if you're downtown, for instance, since there isn't one downtown) isn't likely to be that helpful.