Simon Woodside has set up a mailing list for:
Discussion about long-distance/rural wireless data connections, point-to-point, point-to-multipoint, long-haul, back-haul, whatever. Generally oriented toward commodity, open-spectrum products, like 802.11b (Wi-Fi), 802.11a, 802.11g, etc.

Here’s the wireless-longhaul Info Page, and here’s the currently pretty empty list archive.