Personal Number (PN) service or Follow-me service allows a user to access telecommunication services with any terminal (e.g., fixed telephones or mobile phones) in any location within the service area. To provide this feature, the PN user needs to manually register with a phone number every time he/she enters a new location. If the user forgets to register the new phone number, the incoming calls will be misrouted. To provide user-friendly follow-me service, this paper proposes an automatic follow-me service (AFS) approach that automatically updates the PN records in the Follow-me database. The significance of our approach is that AFS can be integrated with existing Follow-me databases to automate PIN services offered by different PSTN service providers. We show how AFS can be implemented by using the Voice over IP and Bluetooth technologies. Then, we propose an analytic model to investigate the performance of AFS. The analytic results are validated by simulation experiments. Our study suggests how to select polling frequency to optimize the AFS performance.