If i understand your question correctly. You have one computer that has an internet connection and several others that dont. You want all computers to connect to the internet through the one computer that has an internet connection?
not sure why you wouldnt want to use a switch or better yet, a small home router.
I suppose you could get wireless network cards or wireless usb adaters for all computers. Set up internet connection sharing on the internet connected machine. without a DHCP server all your computers (2000, XP or Vista) will get an automatic IP address (169.254.x.x). they could then connect add-hoc to the internet connection machine and get out to the inernet.