An apparatus and method are provided for entering and transmitting a message at a future delivery time to a receiving device that is coupled either to a telephony-centric network or to a data-centric network. The apparatus includes a message server, a data-centric network server, and a telephony-centric network server. The message server translates the message into a format compatible with the receiving device and initiates delivery of the message at the future delivery time. The data-centric network server transmits the message over the data-centric network and, if the receiving device is addressable over the data-centric network, then said data-centric network server delivers the message directly to the receiving device. The telephony-centric network server provides an interface between the data-centric network server and the telephony-centric network. If the receiving device is addressable by the telephony-centric network, then the telephony-centric network server receives the message from said data-centric network server and delivers the message to the receiving device over the telephony-centric network.