There are too many variables here - please advise what kind of ADSL connectivity you have. If you don't have it yet, perhaps the simplest and easiest way to do it is to deploy a connectivity device that combines router capabilities in the box. Then all you do is connect the box to a switching hub (use the uplink port - the one usually marked differently from the others, or combined with one of the others as an 'OR' device), connect all your computers into the hub as well, and away you go...