In a packet-switched network, a subscribing application subscribes to a network presence server to receive selected network presence information. The network presence server obtains the selected network presence information, at least in part, from status messages that a network access server, such as a packet data serving node (PDSN), sends, for example, to an accounting server. The network presence server then provides the selected network presence information to the subscribing application. The selected network presence information may include an identification of a particular customer that has just initiated or terminated a data session and the network address the particular customer is or was using.