Nah, with any broadband connection, you can only connect with one IP address to the ISP, which is why you cant connect the modem to the Uplink port and then share it that way. If you do that, only one computer can use it any one time, and thats the computer that hijacks the IP needed.
That's why we have routers. A router is like a mini computer that has its own IP and so can share the internet just as ZeGoat has done except ZeGoat has used a proper computer.
Oh and if you want to check your IP, go to start, select run, type in cmd (or command) and press enter. then in the DOS-style window, type in ipconfig and it'll show you your IP address,.