Can you be a little more specific?
Like,
"I have a computer at one house connected to cable modem. I have a 3 computer network setup at my other, how can i add the single computer at the other house to my network?"
I *THINK* thats what your trying to get at, if thats the case, you need to create a VPN, do a search on goole for your operating system + VPN, i.e. "windows 2000 VPN"