The warchalking site has a discussion going on about what form the warchalking icons should take. One side, the "more is more" crowd, wants to create lots of icons that carry lots of information. Frankly, most of it is information only a techie could love.
My organization networks over 250 buildings for 22,000 employees. We're also in the planning phase of deploying Wi-Fi access points at places where cops hang out so they can connect to the net during their shift (they use CDPD for low bandwidth ops, but need a high bandwidth option sometimes). In this kind of environment, warchalking has some important uses beyond finding a free net. I'm hoping to use warchalking icons to alert employees to the existence of wireless nets in conference rooms and other places.
Given all this, I have to come down in the less is more camp. The icons need to be kept simple and relatively few if we expect them to be used.