For the general case of connecting to a Wi-Fi network, we recommend that you use the wpa_supplicant daemon.
It handles unsecure, WEP, WPA, and WPA2 networks and provides a mechanism for saving network information in a configuration file that's scanned on startup, thereby removing the need for you to constantly reenter network parameters after rebooting or moving from one network domain to another. The information following covers the more specific cases if you don't want to run the supplicant.
You can connect to a wireless network by using one of the following:
Once connected, you need to configure the interface in the standard way: