DHCP question

[Vizion]

My home network is connected by my Linksys Broadband Router model RT31P2 to an upstream Cable company supplied Motorola SB5100 cable modem.

A single IP address is allocated via DHCP to the Linksys to which my private network is attached. The IP address is rarely changed.

I need to monitor and record that IP address and initiate a series of processes if/when the IP address changes.

Suggestions please... and thanks in advance for any replies

david