I've got broadband in (Blueyonder) and use a wireless router to network my desktop and laptop together.
Some advantages of having a router are as follows:-
(1) Any networked computer attached to the router can access the internet without having to have any other machine on.
(2) Normally routers have a good built-in firewall (which is a must for broadband) to stop unwanted snooping.
(3) A wireless (or Wi-Fi) router can also act as an access point for the wireless pc's which will link them to the pc linked by cable to the router (e.g., my desktop is linked by a network cable to the router. The laptop uses the wireless router to access the desktop computer).
(4) Some routers have a built-in print server so you can share a printer over the network meaning that anyone can print without having to have a computer switched on attached to the printer.
(5) It's easy to add more computers to the network as the router will assign it an IP address and should (in theory) be simple to set up.
I'm sure there are many more advantages. I do not know of any sites but a lot of people on this site have routers and a fair few have gone down the wi-fi route so I'm sure there will be more postings.
p.s. the router I have for the Broadband and wireless networking is the Netgear FM114P. It's a good piece of kit. Easy to set up.
When you are looking to buy any more kit (router, wi-fi cards, etc.) post on the helproom and there will be a lot of recommendations for you.