The development of value added services based upon the GSM standard is becoming increasingly important to both network operators and the subscriber's to such networks. This paper outlines a prototype system capable of delivering real time stock (share) price information from internet based stock price servers to mobile subscribers equipped with GSM cellular terminals. The prototype system is based upon a gateway PC system which is connected to both the internet and also the GSM cellular. The system allows a subscriber to the service to receive updates on stock prices at desired intervals throughout the day, or on demand, primarily by means of short messages delivered to their GSM mobile phone. In addition to this primary delivery mechanism, a number of enhanced delivery mechanism have also been designed into the system based around a "dial up" interactive voice response (IVR) system on the gateway PC platform. These allow a subscriber to get an immediate update, by a short message or by a spoken prompt, of some\all of his stock portfolio by dialling up and interacting with the IVR functionality in the system server.