A fairly new site called MetroFreeFi is compiling lists of free wi-fi zones in cities all over, like this list of Los Angeles Hotspots. It’s far from complete, but it’s a start. And they have the cool option of making a WiPod where you can download the list of locations as a note file to your iPod for handy on the go reference. Someone with more free time than me should try to make this list a bit more comprehensive, something like that would be very useful.