Any router (or modem/router in your case; you are an ADSL user, yes?) will do the job, particularly one in which the wireless link can be turned off in the config UI.
The modem goes in the spares box.
Setup? Simple. Just plug the clients to the router with RJ45 Ethernet cables (note that crossovers are not required; patches are fine) click here.
*Only* bother running the NSW (Network Setup Wizard) if you need to share files and printers. Distribution of an internet connection does not require in a router-based network.
Remember to switch to "never dial a connection" in the Connection tab of Internet Options on each client, and remember to configure each client's firewall when it prompts you.