FON is an interesting item. However, in the US where they are also trying to get a 'free' network it is against every TOS from any ISP to redistribute the network (and free isn't the issue).
A lot of people are signing up and hacking the router so that it calls home, as the software setup requires, but isn't open or available to third parties.
I won't discuss how FON is supposed to be making money, as they are certainly losing money on the hardware setup.