Bruce Schneier wrote
this article about his own wireless reservations.
When I think about "open networks" I don't really think wireless is the solution - too anonymous and too easily subverted. My own paranoia tells me to stay away from wireless although I do maintain an open access point in my neighborhood which is mostly populated by retirees and the occasional college student.
I think the closest thing I can think of that sounds, IMO, like an "open network" or "open internet" is George Lucas'
Third Internet.