MyWanIp allows you to discover your WAN IP address.

MyWanIp is a Windows 95,98, ME, NT4, 2000 and XP utility that allows you to discover your WAN IP address. Many home and small business users have broadband routers like the Linksys, D-Link, SMC, Netgear, Cisco, Agere and others between their LAN and their Internet connection. When a LAN PC is connected behind one of these routers, most IP Address utilities will only tell you the LAN IP or private IP address. This is not useful to someone trying to connect to your router or your computer from the Internet. MyWanIP always displays the proper WAN IP Address - the TRUE IP address needed to connect to any PC on the LAN. MyWanIP uses remote servers to determine the Cable/DSL router s true WAN IP address, and shows that IP address in a small window. This allows you to determine the IP address that someone else needs to connect to your computer over the Internet. You can also COPY the displayed IP address into the clipboard for use in an email message.