It would be great to know where free, publicly accessible (municipal or otherwise) hotspots are when travelling in foreign cities. Does such a utility exist (website/app etc.)?
There are several.
Two of the biggest are:
Hope that helps!
Another trick I figured out in Kazakhstan is to search for foursquare.com posts about wifi - for example, I was wondering if Astana airport had free wifi, and indeed, https://foursquare.com/venue/2442553 confirmed that it did, and that it is fast! :)
FON is a community based on wifi sharing. Once you subscribe, you get free access to all other FON wifi hotspots.
There are a lot of these.