If you use a dial-up service, your online-IP will change everytime, that you connect, though. The fastest way to find it, would be to open a Dos-Box and type ipconfig there. You'll get two IPs and the subnet mask. One IP, I think it's the second, will be the one that you've set for your network card (if you have one and if you've set a fixed IP for that, of course) and the one above is the one, that identifies your PC in the internet for the time, that you're logged in. So that's the IP, that your buddy needs to have to connect to your pc.