The FON Google map based locater application works well, hidden in it is the ability to download POIS (points of interest) files which can then be loaded into your GPS. These contain the current list of fonspots for a single country which you select. The official way to get at this data is from the FON maps page, then go to the "Tools" link in the "Menu" box on the left side of the page. Under "Tools" you will find "download to navigation gizmo", click on this and you get to a small form that allows you to pick the country of interest and the file format you want. This only worked for me from the Mozilla Seamonkey browser, both Firefox and MSIE failed to download the file.
You can get this to work by directly entering a URL like this one for Canada. It has a format that looks like:
http://maps.fon.com/main/downloadPois?country_code=ca&format=csv, you can select the different file formats by changing the "csv" at the end (I picked CSV because I wanted to search for all the fonspots in one city) and you can change the country by replacing the "ca" with the country code you are interested in. A note of interest, as of 20-Jan-2008 Canada now has 850 FONspots listed and Calgary has 27.