you will need a wireless router and a wireless enabled device, your laptop may have a wireless card built in if not you will need a wireless reciver nromally these are USB and can be bought from the likes of PC world ETC.
plug your laptop diectrly into the router and login to the router
normally this is using your web brower (Safari) and go to
http://192.168.1.1 but you will have to look in the user guide for your make and model of router.
check to see if your router has wireless enabled.
its reccomended to use a password on your wireless network use WPA2 if you can as WEP is easy to hack.
setup a password and a SSID(Name of the network)
once this is setup save these settings to your router and unplug your laptop from the router.
using the wireless connection wizard (depends on OS as to how to do this)
search for wireless networks find yours and click connect enter your password when it asks for it.
you may have to change the security settings to a lower level of security sometimes windows wont find a network with a high security level for some reason beyond me ( im a Apple Mac Guy)
hope that helps
if you post the make and model of your laptop and router ill be able to help you more.