An approach is provided for offering communication services supported by a data network and a telephony network. A primary identifier is assigned to a user for access to the communication services, wherein the primary identifier is used by a party seeking to communicate with the user via one of the communication services. The primary identifier is mapped to one of a plurality of secondary identifiers corresponding to the respective communication services. The one secondary identifier is used by at least one of the data network and the telephony network to establish a communication session between the party and the user.