Strictly speaking what you're planning is illegal since you'll be providing services over the network across property borders - I believe one needs a VANS license for this.
But since we live in RSA: you'll need a sector antenna mounted high up directed at your 'clients' with a PC running the internet connection etc.
Actually, the law was ammended several years ago, it states that you are not allowed to run any form of communications across government lines.
The act was successfully argued in court that if a radio signal is a form of radiated energy, and the signal being transmitted was the message saying "HELLO" then surely waving at someone across the road was then illegal as light used so you can see said person waving was a form of radiated energy and the signal being transmitted is the message "HELLO".
This guy actually won, and it was then decreed that any form of radiated transmission had to be below a certain mW for it to be legal.
Now taking a standard wireless router that gives out said mW, and attaching a sectoral antenna would mean that most of the signal that was being radiated in all directions would be focused, as if using a magnifying glass with light... the focused signal would have more energy and thus travel further and more successfully.
This means I should be able to cover a large area with out breaking any laws.
Secondly, if I enter into an agreement with my ISP to share my bandwidth with my neighbors then I am in legal grounds there... infact I know for a fact my ISP won't mind... I own it.
Lastly, I enter into an agreement with the connectees that they are not buying into a service, but rather they are sharing an existing service, meaning they are paying for the bandwidth they use only... so technically I wouldn't be a WISP, more like a WUG that promotes the sharing of Internet Connections...
