More than a few Wi-Fi finders are on the Web (including JiWire, started by a former CNET exec), but Earthcode's system wins points for its simplicity and speed. You just select a city and zoom in on your location (using the embedded Google maps), and it will show you Wi-Fi locations that other users have added. If you want to add one yourself, it's very easy, and you can also rate the food and the likelihood of finding a convenient AC outlet for your laptop. I put the CNET lobby (free Wi-Fi, nice tables, no food) in the database before Andre had finished his 60-second pitch.
Andre might want to add a way to find your location on a map (this might be necessary if you're visiting a new city), and it would be helpful if the list view sorted by proximity. And, of course, more entries would be good. But this is a great start.