I found a great site these days indexing all the hotspots of the world (tough job!). The site currently claims to list 118,776 Wi-Fi hotspots in 128 countries.
You can search WIFI connections by location, and filter the results by:
- Office buildings
- Convention centers
The results show the name of the Wifi providers, the type of wifi connection (802.11b 802.11g) and free hotspot are highlighted. You can display a map with all the hotspots close to the one selected like shown below (in the example I have selected Cannes (France) hotspots:
I found out that the map was too small to be efficient at locating a hotspot from a hotspot concentration; it’s like looking for a needle in a haystack. There is no zoom available in this map provided by Mappoint.com (Advice: Google Map Api is available for free, you can zoom all day long without any cost). Anyway this website is worth the try and can sometimes be very helpful.