Not all wireless networks have an internet connection. That sounds like exactly what you are seeing. I use a program called Winc from cirond corporation
While there are other sniffers out there, I really like this one, cuz it shows the connections, and also actually start the browser and lets you select it AND CONNECT
If nothing else, check it out, it's free to try for 30 days. I highly recommend it. What do you have to lose?
PS. For those with PDA's that have WiFi (like my iPAQ 4551), they also have a product called MiniWinc
Don't be put off by the website, it's actually a security testing company, but they have really neat programs (not affiliated with the company, just a very happy user)