Go to eBuyer and look at the adsl routers.
These days you can get an adsl wireless modem router for virtually the same price as a non-wireless one and this will give you more flexibility in the future. If yo choose this, make sure the wireless standard is 802.11g, not 11b which is slower.
You will also need 2 ethernet cables long enough to connect your pcs to the router (the router will come with one, but normally only 1 metre long).
If the router's firewall is important to you, make sure that the spec of the one you buy has a firewall - nearly all do.