A method and a system for notifying a subscriber of the occurrence of an event, which may be a messaging event, in which a message is received by a messaging service associated with the particular subscriber; or a non-messaging event, such as the occurrence of a particular stock price. For example, an e-mail message is optionally received by the mailbox of the subscriber, which is detected by the notification request sender according to the present invention. The notification request sender then prepares a notification request according to a standard network protocol, such as HTTP for example, for transmission to a notification server for the subscriber. This server parses the notification request, and notifies the subscriber with a message according to a particular messaging service, such as an SMS (short message system) message sent to a cellular telephone of the subscriber, for example. Optionally and preferably, if a plurality of such messaging systems for notifying the subscriber is available, then the notification server determines the best messaging system or systems for notifying the subscriber, for example according to the preference of the subscriber.