Patrizia, How is what you are offering any different from what now a BUNCH of companies are offer, including one that has done it the longest?
What is the benefit of incorporating WiFi into the formula, for the end user that has no WiFi?
What you are proposing is already being done, although, another company still started a similar project last week. These projects will be worthless unless they are ALL connected together . Like IPtel.org and FWD do now, where one can call IPtel from FWD. When this happens, yes these services will offer a trmendous benefit. Now, however I have friends on FWD and SIP Phone (not IPTEL), I have to have 2 DIFFERENT services to call them both. If you want your service to succeed, connect it with every other service provider you can find for direct IP to ip calling, even the Deltathrees and the Packet8s