I am complete network newbie. My neighbors and I made a home network between our computers. The whole idea was to share one cable modem and connection for using the Internet. Because of its speed, it can satisfy all our needs and we would spend less money each. However, that is not working. A friend told me that my wireless G router probably won't forward ports.
I don't think that your problems are connected with your router. With router, you should just pay attention that not all the ports on it could be shared. I think that your connection is not working because you probably did not share it properly. There are few standard ways for sharing internet connections. The thing you should do if you want to share cable internet connection is called port forwarding. That is related with TCP/IP settings and static IP address. If you want to do that with software emulation, you must have some stronger experience. I must assume that you do not have that so let us get back to the hardware solution. To do port forwarding you will need a special device called network router. When you connect your network and cable modem to router, you will not have any further problems with accessing the Internet over your cable connection. The other thing you can do is to connect one computer, which must always be turned on, to cable network as a gateway and share its connection to everybody else.