Most laptops nowadays ship with Wireless inside, and even if it does not there are many options to add a Wireless device to your laptop.
NetworkManager [1,2] is a service that runs on your system that allows you to easily set up your network connection, and it is especially useful if you need to configure a wireless connection. Unfortunately, by default NetworkManager is disabled so we have to enable it.
Starting the NetworkManager service
First we are going to configure your CentOS system to automatically start the NetworkManager on startup. You can do this by running:
chkconfig NetworkManager on
Then we are going to start it so we can use it right away without needing to reboot:
service NetworkManager start
If you have done that in your graphical environment (Gnome), your Notification Area (usually in the Gnome panel on the top-right) will show a new icon. If you left-click on this icon, you will see a list of possible Wireless networks to connect to.
You may also want to disable the network and wpa_supplicant services at boot time, as NetworkManager will now handle these. For this, simply do:
chkconfig network off chkconfig wpa_supplicant off
There is nothing more to it !
Useful hint: The request for the keyring password, when using NetworkManager, can be suppressed by using the pam_keyring package, as described in reference . The pam_keyring package can be obtained from the RPMForge repository.
 http://fedoraproject.org/wiki/Tools/NetworkManager (some gnome- and kde-specific info)