If you want to share your broadband connection amongst PC's you need a router, a switch or hub will not work, switches / hubs are ok for networking PC's together but to make that shared connection to the Internet you should have a router. There are other ways of doing it, with 2 NIC's in the PC connected to the BB but the router is the best way.
Edit:- Welcome by the way !
You might want to look at this thread....
http://www.cableforum.co.uk/board/showthread.php?t=8269