Your IP Address is a unique number that identifies your computer across networks. It is similar to a telephone number.
Depending on the way your network is set up, your IP address may remain static (static IP) or will change everytime you log on to the internet (dynamic IP). Generally speaking, dial-up internet uses dynamic IP and broadband internet generally uses static IP.
If you are behind a router, the IP address you see here may be identicle to the IP addresses of other computers behind the same router.