One of the things my city has done right is to have free wifi downtown, by the museums and river walk. The system was put in for the police and opened in certain areas to all. In my neighborhood my N800 sees the Police hotspot but won't let me log in. But, where it is allowed it works well. I live in a town with about 100,000.

McDonalds uses Wayport and Krystal is open and free. Some iPass at hotels. I've been told the Barnes and Noble book store is free. At several shopping centers Quiznos has free wifi and so does Staples.
If you're an AT&T High Speed Internet Pro, Elite, Fast Access DSL Xtreme, Xtreme 6.0 or AT&T U-verse customers you are already signed up for free. I haven't tried that yet but apparently it's the provider at the UPS stores. One morning I was at a neighborhood Ace Hardware and I logged on to check my e-mail. I couldn't believe that one hospital here offers open wifi and the other doesn't.

Good luck with your research.