I am having a similar problem. I have a 2gen 32gb ipod touch. When I am in areas with free public access, it connects but safari won't work. And yes the ip address was there, DNS and router. And yes I did renew lease and resetted the network settings. I have tried at different public access areas and same thing. It does work when I am at home and when I am friends with wireless.
I also have Boingo app, which when I am near there hotspots it should automatically connect me. But I've gone to there hotspots and nothing. Maybe I'm doing something wrong but I've done alot of research on this.
I did find a thread with people having the same problem. They could connect at home but not in free public access areas. It is apparently an internal issue, they exchanged there's for new ones and had no problems with it after. I'd debating doing the same.