I intend to put my Raspberry Pies to work as intelligent controllers. As long as they stay at home I can easily keep track of the IP addresses they get from my modem. However as soon as my Pies start roaming the world and get connected to strange networks it is not as simple any more.

This little script will help you determine the IP address the Raspberry Pi has received. As soon as the Raspberry Pi receives an IP address from the network’s DHCP server it will send a Tweet, telling what IP address it has received. It can even tell you with what IP address it is now connected to the internet if you want to.

Full article here:
Tweet My IP (SB-Projects On Line)

Related article from same site: Send Twitter messages (from your Raspberry Pi)