What is FON, you may ask? Well, it's kind of like a home exchange for network access points. If you use their router to set up your location as an access point for FON members, then you get to use any other FON member's access point absolutely free. If you're not a member, you can still use it for a nominal fee of $2 a day. You can also be a Linus - you give your bandwidth for free and you get free access to access points - or a Bill - you want to get a cut of the fees an Alien pays (someone not in the FON network). I'm a Linus, of course :)
They have a great Google Map mashup that lets you search for access points. Just for kicks I looked in my neighborhood, and found at least a dozen within a mile of my house. I also checked out Prague, since I'll likely be going there soon, and again, at least a dozen in the downtown vicinity.
They are insidious and sneaky in a fun way, too.
Check out this blog where they offer you a free FON router and a 50% cut of the fees if you live near a Starbucks.
Now, I suspect many of these access points are at people's homes. So what does that mean? Do I have to sit in my car or on the sidewalk sucking bits like a homeless net-vampire? Ah, well. At least, when I just have to send out that email or post that blog, I know I'll always be able to find a friendly signal in my neighborhood.