A computer-implemented system is provided, including a network consisting of the Internet, PSTN, and CATV network. The network is connected to multiple users' client systems, and also to multiple service provider systems. Each user has a user profile stored in a User Preference Database, while each service provider has service parameters defining the type of its service stored in a Service Database, both of which are connected to the network. The system further includes a Gatekeeper Server, which establishes voice communication among the client systems and the service provider systems. In operation, upon receiving a user's request for service, the Gatekeeper Server identifies one or more service providers whose service parameters match the user's request for service and the user's profile. Upon the user's selection of one such service provider, the Gatekeeper server automatically selects and establishes a preferred mode of voice connection between the user and the selected service provider.