You have a fundamental contradiction. First you talk about global wireless, then you talk about community wireless. Global wireless is completely impractical to even consider. Community wireless can work in some densely populated neighborhoods. Geography matters. You need to clarify what your goals are in this regard.

Another problem is that you aren't discussing economics at all! Costs matter. Any project like this which is not primarily concerned with costs and economics has no chance of success.

How will you allocate the resources of your network? Surely you have heard of the tragedy of the commons. That refers to the problem of people over-using a common resource when they don't have to pay for it. In this context that means that some people will use more than their "fair share" of bandwidth.

You need a mechanism to decide how much bandwidth each person deserves, and how much each person must contribute. From each according to their ability, to each according to their needs? I think history has shown that that doesn't work too well. From and to each according to their ability to pay? That will work but perhaps doesn't fit into your utopian philosophy.

I think you'll find that as you move from broad generalizations to specific implementations, you will have to make compromises which will dilute the ideology and fragment your supporters. In the end you will have a community divvying up the cost of a T-1 line. Presto, you've re-invented the community ISP, maybe this time with wireless connections. As I said, it can probably work in some areas, but it's not going to change the world.

Is there a good resource anywhere giving instructions on how to share your wireless network? Like, technical details on how to do it, steps you should take to make sure that your computers are safe, etc. Airport/OS X specific information would be good, but not crucial.