Now you don’t need sniffers and chalk anymore. The Premier Online WiFi Location Directory, launched a free searchable database today, featuring over 8,900 WiFi HotSpot locations representing 136 Network Providers worldwide. 
Of course one person’s ‘worldwide’ is another person’s ‘Hey! Why d’ya leave out my country? Not WiFi-ey enough for ya?’. I couldn’t find anything in Singapore, only one place was listed in Thailand and the Philippines threw up a ‘records not found!!!’ [sic] message. Sadly, this kind of thing is a mug’s game: Getting an uptodate list and keeping it uptodate with something like WiFi is a thankless, neverending task.