James:
What M.B. is describing in his letter “Post Disaster Wi-Fi Commo Networks” is ideally served by a mesh network. I’d suggest starting at the Open Mesh web site. Click the Support link for tutorials and frequently asked questions (FAQs).
If you want to link up a neighborhood this can work fairly well. Mounting the radios outside helps considerably and will often be required as the 2.4 GHz signal doesn’t penetrate obstructions very well. Existing wireless routers, old 2.4 GHz cordless phones, etc may interfere. If radio links are more than a few hundred feet apart you’ll need to get creative: find a way to get clear line-of-sight between adjacent radios, use directional antennas or at least upgraded omni’s, make friends with someone on high ground between you and your friends, run Ethernet between radios on opposite sides of buildings, etc.
Make sure that you can work with your geography before buying lots of hardware. All too often obstructions are going to be an insurmountable problem. Most mesh networks are dependent on multiple wired connections to the Internet to hold separate portions of the mesh together, which won’t be an option in a grid-down scenario.