A call between a calling party and a called party, one or both of whom may be subscribers to Internet Telephony (IT) services, commences upon the receipt of a call dialed by the calling party to the Plain Old Telephony Service (POTS) number associated with the calling party. A first hub receives the call and routes it to the called party if that party is not an IT services subscriber that is currently on line. If the called party is an IT services subscriber that is on-line, the call is received at an Internet Services Provider serving the called party. The ISP converts the call to an IT format if the call is not already in that format and thereafter delivers the call to the called party.