There are places to gain public access legally.
College Campuses. In many areas there are colleges that specifically allow anonymous public access.
Also check: Coffeeshops, LAN gaming centers\clubs, Libraries and of course, do some searches inyour area for wifi community projects. Portland Oregon for instance has a community scene as does San Fran off the top of my head. Of course there is the one at Burning Man for a week :) Also, there are a lot of smallish private ones, and word of mouth, warchalking.org etc. allows people to upload their sites so when you are driving around you can check movie schedules etc.
Just remember to be polite, and don't break into or launch illegal activities from the network kind enough to provide it- they will be forced to remove access if it is abused. If I was on a community wifi connection and they had a security problem, telling them would probably go a lot farther than say, telling a bank IMO, but use your own judgement.
Also, remember, sessions are a 2 way street! Protect your privacy and share what is public and you want to share! You will find that not only the netadmins but other guests on an open wap will potentially be looking back at you! :)
~ Have fun, be safe!