I had bit of a nightmare getting wireless to work properly so I put together this howto hoping it will help others. This was done on a raspberry pi running raspbian (wheezy).
sudo apt-get install wireless-tools wpasupplicant
get your psk using the following command where yourssid is your SSID’s name ie HOME and where passphrase is your wireless password ie PASSWORD123
wpa_passphrase yourssid yourpassphrase
Using my examples above this should output the following
From this copy the psk string then
sudo nano /etc/wpa_supplicant/wpa_supplicant.conf
and insert it onto the psk line and edit the SSID name, save and exit.
sudo nano /etc/network/interfacesand add the following (obviously adjust it to your network setup ie static etc), save and exit
iface lo inet loopback
iface eth0 inet dhcp
iface wlan0 inet dhcp
pre-up wpa_supplicant -Dwext -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf -B
Now I had a problem whereby wirless was only bougth up when the wired conneciton was plugged, obviously this defeats the whole object of wireless so I managed to come up with this fix
sudo nano /etc/default/ifplugd and add the following
# This file may be changed either manually or by running dpkg-reconfigure.
# N.B.: dpkg-reconfigure deletes everything from this file except for
# the assignments to variables INTERFACES, HOTPLUG_INTERFACES, ARGS and
# SUSPEND_ACTION. When run it uses the current values of those variables
# as their default values, thus preserving the administrator's changes.
# This file is sourced by both the init script /etc/init.d/ifplugd and
# the udev script /lib/udev/ifplugd.agent to give default values.
# The init script starts ifplugd for all interfaces listed in
# INTERFACES, and the udev script starts ifplugd for all interfaces
# listed in HOTPLUG_INTERFACES. The special value all starts one
# ifplugd for all interfaces being present.
ARGS="-q -f -u0 -d10 -w -I"
Save and exit then reboot and hopefully your wireless interface will be bought up and connect successfully.