Run these commands:
sudo -i
apt-get -y install libnl-dev wget http://download.aircrack-ng.org/aircrack-ng-1.2-rc2.tar.gz tar -zxvf aircrack-ng-1.2-rc2.tar.gz cd aircrack-ng-1.2-rc2
make make install
airodump-ng-oui-update apt-get -y install iw sudo apt-get install ethtool airmon-ng start wlan0
The airodump-ng-oui-update will take a while to complete.
Looking out for networks
airodump-ng mon0
Information taken from here: http://www.aircrack-ng.org/doku.php?id=newbie_guide