From: "My List Mail" <mylistmail at gmail dot com>

> is there any opensource?

> or if not opensource at least will allow to install several locations
> using only 1 hotspot server

I am not sure what you are asking here.  Do you want a billing system, or do 
you want to interface with one?  There are several ways to do accounting, 
such as free RADIUS, but credit cards charge to use them, and so any service 
which uses credit cards can not be free.  So, what "exactly" do you want to 
do, what do you have, and what do you need?

                        Lee