Freifunk is a german initiative of private people operating a wireless netwerk througout cities and communities. The basic goals are interconnecting neighborhoods and communities to data networks but also getting together and modifying Wi-Fi hardware, basically a bunch of geeks that create large wireless networks for fun and information exchange.
The Wiki from the Leipzig Project Group features a compact guide on ourdoor mounting and usage of indoor Wi-Fi devices.
If you speak german and plan on setting up an antennae a router or maybe even joining an open network community you will find some quick and effective setup guides on mounting your devices without them being exterminated by the forces of nature (pictures included 😉 ) Its best to have a helpful and nifty community member handy to pimp your Wi-Fi
Find a freifunk near you http://start.freifunk.net/