1. Internet Connection Sharing. Part of MS Windows sincd Windows 98 SE. One computer connected to the telco line, other computer connected to the first. First computer serves as software router, so to speak.
2. Some broadband routers have possibility of dial-up in case broadband (cable, ADSL) doesn't work. Buy one of those. Here's an example: http://www.duxcw.com/dcforum/DCForumID2/1358.html
Hope this helps.
Is it possible to connect two or more computers via only one phone connection with a 56K modem and a router or a switcher?