You would need to buy an ethernet card for your PC, these cost upward of £1.99 thesedays and fitting them is not something you should get worried about, you turn the power off, open the case and push it into a spare slot. Windows should do the rest.
http://www.ebuyer.com/customer/produ...duct_uid=31095
You then need a wireless router, the Linksys WRT54G or something else from the list of recommendations.
http://www.cableforum.co.uk/board/article.php?a=74
You will need to secure your wireless network
http://www.cableforum.co.uk/board/article.php?a=12
Do the laptops have wireless functionality already?