Even if you've managed to find an Internet connection for yourself, it won't be that helpful in reaching out to your fellow locals if they can't get online to find you. If you're trying to coordinate a group of people in your area and can't rely on an Internet connection, cell phones, or SMS, your best bet could be a of sorts--essentially, a distributed network of wireless networking devices that can all find each other and communicate to each other. Even if none of those devices have a working Internet connection, they can still find each other, which, if your network covers the city you're in, might be all you need. At the moment, wireless mesh networking isn't really anywhere close to market-ready, though we have seen an implementation of the 802.11s draft standard, which extends the 802.11 Wi-Fi standard to include wireless mesh networking, in the .
However, a prepared guerrilla networker with a handful of PCs could make good use of ($25, 30-day free trial), an app which piggybacks on your Wi-Fi adapter driver to turn your normal ad-hoc Wi-Fi network into a multi-hop ad-hoc network (disclaimer: We haven't tried this ourselves yet), meaning that instead of requiring each device on the network to be within range of the original access point, you simply need to be within range of a device on that network that has Daihinia installed, effectively allowing you to add a wireless mesh layer to your ad-hoc network.
Advanced freedom fighters can set up a portal Web page on their network that explains the way the setup works, with Daihinia instructions and a local download link so they can spread the network even further. Lastly, just add a Bonjour-compatible chat client like or iChat and you'll be able to talk to your neighbors across the city without needing an Internet connection.