From Barefoot Productions:
IP Monitor displays a computer's name and IP address in a window. If notification features are turned on, when the IP address changes, it can be sent to an email address and/or an FTP server to notify of the changes. This is useful for computers that have dynamically assigned IP addresses, but need to be accessed remotely. Version 5.1 includes service module for Windows 2000/XP, security features, and integration with Windows XP/SP2 firewall.