Bueno, encontré esta utilidad que a mi me sirvió y espero que a uds. también.
DHCP Alerter is a Windows 2000/XP service that provides remote and local alerting service and logging for dynamic ip address changes. It alerts via email, pop-up window, and log file. The alert contains both the old and new ip address. It is useful for anyone who wants to remotely access a computer configured with DHCP. This includes the vast majority of cable modem and DSL users out there. If your internet service provider should change your ip address, you will be sent the new one immediately. Additionally, you can keep track of when and how frequently ip changes occur. If you run any web, ftp, or other internet services through a cable modem or DSL line, you need this tool.
Es gratis para uso no comercial, y pueden bajarlo de http://educing.com/dhcpalerter/